Clipping in reference picture resampling

ABSTRACT

A method of video processing includes making a first determination about whether a decoder-side motion vector refinement (DMVR) tool is enabled for a conversion between a current block of a current picture of a video and a coded representation of the video; making a second determination, based on the first determination, about whether or how to clip a motion vector according to a bounding block for reference sample padding in a reference picture used for determining a prediction block for the current block according to a rule, and performing the conversion based on the first determination and the second determination. By using the DMVR tool, an encoded motion vector from the coded representation is refined prior to using for determining the prediction block.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CN2020/110768, filed on Aug. 24, 2020, which claims the priorityto and benefits of International Patent Application No.PCT/CN2019/102289, filed on Aug. 23, 2019, International PatentApplication No. PCT/CN2019/112820, filed on Oct. 23, 2019 andInternational Patent Application No. PCT/CN2019/129959, filed on Dec.30, 2019. All the aforementioned applications are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

This patent document relates to video coding and decoding.

BACKGROUND

In spite of the advances in video compression, digital video stillaccounts for the largest bandwidth use on the internet and other digitalcommunication networks. As the number of connected user devices capableof receiving and displaying video increases, it is expected that thebandwidth demand for digital video usage will continue to grow.

SUMMARY

Devices, systems and methods related to digital video coding, andspecifically, to video and image coding and decoding in which currentpictures and references pictures have different sizes or resolutions.

In one example aspect, a method of video processing is disclosed. Themethod includes making a first determination about whether adecoder-side motion vector refinement (DMVR) tool is enabled for aconversion between a current block of a current picture of a video and acoded representation of the video; making a second determination, basedon the first determination, about whether or how to clip a motion vectoraccording to a bounding block for reference sample padding in areference picture used for determining a prediction block for thecurrent block according to a rule, and performing the conversion basedon the first determination and the second determination; wherein, usingthe DMVR tool, an encoded motion vector from the coded representation isrefined prior to using for determining the prediction block.

In another example aspect, another method of video processing isdisclosed. The method includes making a first determination aboutwhether reference picture wrapping is enabled for a conversion between acurrent block of a current picture of a video and a coded representationof the video; making a second determination, based on the firstdetermination, about whether or how to clip a motion vector according toa bounding block for reference sample padding in a reference pictureused for determining a prediction block for the current block accordingto a rule, and performing the conversion based on the firstdetermination and the second determination.

In another example aspect, another method of video processing isdisclosed. The method includes making a first determination aboutwhether a coding tool is enabled for a conversion between a currentblock of a current picture of a video and a coded representation of thevideo; making a second determination, based on the first determination,about whether or how to clip chroma or luma samples to integer positionsin a reference picture used for determining a prediction block for thecurrent block according to a rule, and performing the conversion basedon the first determination and the second determination.

In another example aspect, another method of video processing isdisclosed. The method includes determining, for a conversion between avideo comprising a current picture comprising a current block and acoded representation of the video, whether an integer sample clippingoperation is to be performed when generating a prediction block for thecurrent block from one or more reference pictures from two referencepicture lists, and performing the conversion based on the determining,wherein the rule is based on a first size associated with the currentpicture and/or a second size associated with the one or more referencepictures in the two reference picture lists or whether use ofdecoder-side motion vector refinement (DMVR) is enabled in which amotion vector coded in the coded representation is refined prior to thegenerating of the prediction block.

In another example aspect, another method of video processing isdisclosed. The method includes deriving, for a conversion between avideo comprising a current picture comprising a current block and acoded representation of the video, a top-left coordinate of a boundingbox for reference signal padding in a reference picture used fordetermining a prediction block for the current block according to arule, and performing the conversion based on the deriving, wherein therule is based on a dimension of the current picture or a dimension ofthe reference picture.

In another example aspect, another method of video processing isdisclosed. The method includes determining, for a conversion between avideo comprising a current picture comprising a current block and acoded representation of the video, whether an integer sample clippingoperationistobeperformedwhengeneratingapredictionblockforthecurrentblockfromareferencepictue,and performing the conversion based on the deriving, wherein the rule isbased on a first size associated with the current picture and/or asecond size associated with the reference picture.

In yet another representative aspect, the above-described method isembodied in the form of processor-executable code and stored in acomputer-readable program medium.

In yet another representative aspect, a device that is configured oroperable to perform the above-described method is disclosed. The devicemay include a processor that is programmed to implement this method.

In yet another representative aspect, a video decoder apparatus mayimplement a method as described herein.

In another example aspect, a computer readable storage medium isdisclosed. The medium includes a coded representation of a video that isgenerated according to a method described in the present document.

The above and other aspects and features of the disclosed technology aredescribed in greater detail in the drawings, the description and theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A 16×16 block is divided into 16 4×4 regions.

FIG. 2A-2C show examples of specific positions in a video block.

FIG. 3 is a block diagram of an example implementation of a hardwareplatform for video processing.

FIG. 4 is a flowchart for an example method of video processing.

FIG. 5 shows an example of wrap-around clipping in VVC.

FIG. 6 is a block diagram of an example implementation of a video codingsystem.

FIG. 7 is a block diagram of an example implementation of a videoencoder.

FIG. 8 is a block diagram of an example implementation of a videodecoder.

FIGS. 9A to 9H show various tables that exemplify embodiments ofdisclosed techniques.

FIGS. 10A to 10F are flowcharts for example methods of video processing.

DETAILED DESCRIPTION

Embodiments of the disclosed technology may be applied to existing videocoding standards (e.g., HEVC, H.265) and future standards to improvecompression performance. Section headings are used in the presentdocument to improve readability of the description and do not in any waylimit the discussion or the embodiments (and/or implementations) to therespective sections only. Furthermore, in the present document, someembodiments described in the context of H.265 use corresponding sectionnumbers of the current VVC specification publication. Furthermore, theuse of “ . . . ” indicates that the remaining portion of the current VVCspecification publication continues without further modification.

1. Introduction

This document is related to video coding technologies. Specifically, itis related to adaptive resolution conversion in video coding. It may beapplied to the existing video/image coding standard like HEVC, or thestandard (Versatile Video Coding) to be finalized. It may be alsoapplicable to future video coding standards or video codec.

2. Initial Discussion

Video coding standards have evolved primarily through the development ofthe well-known ITU-T and ISO/IEC standards. The ITU-T produced H.261 andH.263, ISO/IEC produced MPEG-1 and MPEG-4 Visual, and the twoorganizations jointly produced the H.262/MPEG-2 Video and H.264/MPEG-4Advanced Video Coding (AVC) and H.265/HEVC standards. Since H.262, thevideo coding standards are based on the hybrid video coding structurewherein temporal prediction plus transform coding are utilized. Toexplore the future video coding technologies beyond HEVC, Joint VideoExploration Team (JVET) was founded by VCEG and MPEG jointly in 2015.Since then, many new methods have been adopted by JVET and put into thereference software named Joint Exploration Model (JEM). In April 2018,the Joint Video Expert Team (JVET) between VCEG (Q6/16) and ISO/IEC JTC1SC29/WG11 (MPEG) was created to work on the VVC standard targeting at50% bitrate reduction compared to HEVC.

AVC and HEVC does not have the ability to change resolution withouthaving to introduce an IDR or intra random access point (IRAP) picture;such ability can be referred to as adaptive resolution change (ARC).There are use cases or application scenarios that would benefit from anARC feature, including the following:

-   -   Rate adaption in video telephony and conferencing: For adapting        the coded video to the changing network conditions, when the        network condition gets worse so that available bandwidth becomes        lower, the encoder may adapt to it by encoding smaller        resolution pictures. Currently, changing picture resolution can        be done only after an IRAP picture; this has several issues. An        IRAP picture at reasonable quality will be much larger than an        inter-coded picture and will be correspondingly more complex to        decode: this costs time and resource. This is a problem if the        resolution change is requested by the decoder for loading        reasons. It can also break low-latency buffer conditions,        forcing an audio re-sync, and the end-to-end delay of the stream        will increase, at least temporarily. This can give a poor user        experience.    -   Active speaker changes in multi-party videoconferencing: For        multi-party video conferencing it is common that the active        speaker is shown in bigger video size than the video for the        rest of conference participants. When the active speaker        changes, picture resolution for each participant may also need        to be adjusted. The need to have ARC feature becomes more        important when such change in active speaker happens frequently.    -   Fast start in streaming: For streaming application, it is common        that the application would buffer up to certain length of        decoded picture before start displaying. Starting the bitstream        with smaller resolution would allow the application to have        enough pictures in the buffer to start displaying faster.

Adaptive stream switching in streaming: The Dynamic Adaptive Streamingover HTTP (DASH) specification includes a feature named@mediaStreamStructureId. This enables switching between differentrepresentations at open-GOP random access points with non-decodableleading pictures, e.g., CRA pictures with associated RASL pictures inHEVC. When two different representations of the same video havedifferent bitrates but the same spatial resolution while they have thesame value of @mediaStreamStructureId, switching between the tworepresentations at a CRA picture with associated RASL pictures can beperformed, and the RASL pictures associated with the switching-at CRApictures can be decoded with acceptable quality hence enabling seamlessswitching. With ARC, the @mediaStreamStructureId feature would also beusable for switching between DASH representations with different spatialresolutions.

ARC is also known as Dynamic resolution conversion.

ARC may also be regarded as a special case of Reference PictureResampling (RPR) such as H.263 Annex P.

2.1. Reference Picture Resampling in H.263 Annex P

This mode describes an algorithm to warp the reference picture prior toits use for prediction. It can be useful for resampling a referencepicture having a different source format than the picture beingpredicted. It can also be used for global motion estimation, orestimation of rotating motion, by warping the shape, size, and locationof the reference picture. The syntax includes warping parameters to beused as well as a resampling algorithm. The simplest level of operationfor the reference picture resampling mode is an implicit factor of 4resampling as only an FIR filter needs to be applied for the upsamplingand downsampling processes. In this case, no additional signalingoverhead is required as its use is understood when the size of a newpicture (indicated in the picture header) is different from that of theprevious picture.

2.2. Contributions on ARC to VVC

Several contributions have been proposed addressing ARC, as listedbelow:

JVET-M0135, JVET-M0259, JVET-N0048, JVET-N0052, JVET-N0118, JVET-N0279.

2.1 ARC in JVET-O2001-v14

ARC, a.k.a. RPR (Reference Picture Resampling) is incorporated inJVET-O2001-v14.

With RPR in JVET-O2001-v14, TMVP is disabled if the collocated picturehas a different resolution to the current picture. Besides, BDOF andDMVR are disabled when the reference picture has a different resolutionto the current picture.

To handle the normal MC when the reference picture has a differentresolution than the current picture, the interpolation section isdefined as below (section numbers refer to the current VVC standard anditalicized text indicates differences from previous version):

8.5.6.3.1 General

Inputs to this process are:

-   -   a luma location (xSb, ySb) specifying the top-left sample of the        current coding subblock relative to the top-left luma sample of        the current picture,    -   a variable sbWidth specifying the width of the current coding        subblock,    -   a variable sbHeight specifying the height of the current coding        subblock,    -   a motion vector offset mvOffset,    -   a refined motion vector refMvLX,    -   the selected reference picture sample array refPicLX,    -   the half sample interpolation filter index hpelIfIdx,    -   the bi-directional optical flow flag bdofFlag,    -   a variable cIdx specifying the colour component index of the        current block.        Outputs of this process are:    -   an (sbWidth+brdExtSize)×(sbHeight+brdExtSize) array        predSamplesLX of prediction sample values.        The prediction block border extension size brdExtSize is derived        as follows:

brdExtSize=(bdofFlag∥(inter_affine_flag[xSb][ySb] &&sps_affine_prof_enabled_flag))?2:0   (8-752)

The variable fRefWidth is set equal to the PicOutputWidthL of thereference picture in luma samples.The variable fRefHeight is set equal to PicOutputHeightL of thereference picture in luma samples.The motion vector mvLX is set equal to (refMvLX−mvOffset).

-   -   If cIdx is equal to 0, the following applies:        -   The scaling factors and their fixed-point representations            are defined as

hori_scale_fp=((fRefWidth<<14)+(PicOutputWidthL>>1))/PicOutputWidthL  (8-753)

vert_scale_p=((fRefHeight<<14)+(PicOutputHeightL>>1))/PicOutputHeightL  (8-754)

-   -   -   Let (xIntL, yIntL) be a luma location given in full-sample            units and (xFracL, yFracL) be an offset given in 1/16-sample            units. These variables are used only in this clause for            specifying fractional-sample locations inside the reference            sample arrays refpicLX.        -   The top-left coordinate of the bounding block for reference            sample padding (xSbInt_(L), ySbInt_(L)) is set equal to            (xSb+(mvLX[0]>>4), ySb+(mvLX[1]>>4)).        -   For each luma sample location        -   (x_(L)=0 . . . sbWidth−1+brdExtSize, y_(L)=0 . . .            sbHeight−1+brdExtSize) inside the prediction luma sample            array predSamplesLX, the corresponding prediction luma            sample value predSamplesLX[x_(L)][y_(L)] is derived as            follows:            -   Let (refxSb_(L), refySb_(L)) and (refx_(L), refy_(L)) be                luma locations pointed to by a motion vector                (refMvLX[0], refMvLX[1]) given in 1/16-sample units. The                variables refxSb_(L), refx_(L), refySb_(L), and refy_(L)                are derived as follows:

$\begin{matrix}{\mspace{79mu}{{refxSb}_{L} = {( {( {{xSb} ⪡ 4} ) + {{refMvLX}\lbrack 0\rbrack}} )^{*}{hori\_ scale}{\_ fp}}}} & \text{(8-755)} \\{{refx}_{L} = {( {( {{{{Sign}({refxSb})}^{*}( {( {{{Abs}({refxSb})} + 128} ) ⪢ 8} )} + {{x_{L}}^{*}( {( {{{hori\_ scale}{\_ fp}} + 8} ) ⪢ 4} )}} ) + 32} ) ⪢ 6}} & \text{(8-756)} \\{\mspace{79mu}{{refySb}_{L} = {( {( {{ySb} ⪡ 4} ) + {{refMvLX}\lbrack 1\rbrack}} )^{*}{vert\_ scale}{\_ fp}}}} & \text{(8-757)} \\{{refy}_{L} = {( {( {{{{Sign}({refySb})}^{*}( {( {{{Abs}({refySb})} + 128} ) ⪢ 8} )} + {{yL}^{*}( {( {{{vert\_ scale}{\_ fp}} + 8} ) ⪢ 4} )}} ) + 32} ) ⪢ 6}} & \text{(8-758)}\end{matrix}$

-   -   -   The variables xInt_(L), yInt_(L) xFrac_(L) and yFrac_(L) are            derived as follows:

xInt_(L)=refx _(L)>>4  (8-759)

yInt_(L)=refy _(L)>>4  (8-760)

xFrac_(L)=refx _(L) & 15  (8-761)

yFrac_(L)=refy _(L) & 15  (8-762)

-   -   If bdofFlag is equal to TRUE or (sps_affine_prof_enabled_flag is        equal to TRUE and inter_affine_flag[xSb][ySb] is equal to TRUE),        and one or more of the following conditions are true, the        prediction luma sample value predSamplesLX[x_(L)][y_(L)] is        derived by invoking the luma integer sample fetching process as        specified in clause 8.5.6.3.3 with (xInt_(L)+(xFrac_(L)>>3)−1),        yInt_(L)+(yFrac_(L)>>3)−1) and refPicLX as inputs.        -   x_(L) is equal to 0.        -   x_(L) is equal to sbWidth+1.        -   y_(L) is equal to 0.        -   y_(L) is equal to sbHeight+1.    -   Otherwise, the prediction luma sample value        predSamplesLX[x_(L)][y_(L)] is derived by invoking the luma        sample 8-tap interpolation filtering process as specified in        clause 8.5.6.3.2 with (xInt_(L)−(brdExtSize>0?1:0),        yInt_(L)−(brdExtSize>0?1:0)), (xFrac_(L), yFrac_(L)),        (xSbInt_(L), ySbInt_(L)), refPicLX, hpelIfIdx, sbWidth, sbHeight        and (xSb, ySb) as inputs.    -   Otherwise (cIdx is not equal to 0), the following applies:        -   Let (xIntC, yIntC) be a chroma location given in full-sample            units and (xFracC, yFracC) be an offset given in 1/32 sample            units. These variables are used only in this clause for            specifying general fractional-sample locations inside the            reference sample arrays refPicLX.        -   The top-left coordinate of the bounding block for reference            sample padding (xSbIntC, ySbIntC) is set equal to            ((xSb/SubWidthC)+(mvLX[0]>>5),            (ySb/SubHeightC)+(mvLX[1]>>5)).        -   For each chroma sample location (xC=0 . . . sbWidth−1, yC=0            . . . sbHeight−1) inside the prediction chroma sample arrays            predSamplesLX, the corresponding prediction chroma sample            value predSamplesLX[xC][yC] is derived as follows:            -   Let (refxSb_(C), refySb_(C)) and (refx_(C), refy_(C)) be                chroma locations pointed to by a motion vector (mvLX[0],                mvLX[1]) given in 1/32-sample units. The variables                refxSb_(C), refySb_(C), refx_(C) and refy_(C) are                derived as follows:

$\begin{matrix}{{refxSb}_{C} = {( {( {{{xSb}/{SubWidthC}} ⪡ 5} ) + {{mvLX}\lbrack 0\rbrack}} )^{*}{hori\_ scale}{\_ fp}}} & \text{(8-763)} \\{{refx}_{C} = {( {( {{{{Sign}( {refxSb}_{C} )}^{*}( {( {{{Abs}( {refxSb}_{C} )} + 256} ) ⪢ 9} )} + {{xC}^{*}( {( {{{hori\_ scale}{\_ fp}} + 8} ) ⪢ 4} )}} ) + 16} ) ⪢ 5}} & \text{(8-764)} \\{{refySb}_{C} = {( {( {{{ySb}/{SubHeightC}} ⪡ 5} ) + {{mvLX}\lbrack 1\rbrack}} )^{*}{vert\_ scale}{\_ fp}}} & \text{(8-765)} \\{{refy}_{C} = {( {( {{{{Sign}( {refySb}_{C} )}^{*}( {( {{{Abs}( {refySb}_{C} )} + 256} ) ⪢ 9} )} + {{yC}^{*}( {( {{{vert\_ scale}{\_ fp}} + 8} ) ⪢ 4} )}} ) + 16} ) ⪢ 5}} & \text{(8-766)}\end{matrix}$

-   -   -   The variables xInt_(C), yInt_(C), xFrac_(C) and yFrac_(C)            are derived as follows:

xInt_(C)=refx _(C)>>5  (8-767)

yInt_(C)=refy _(C)>>5  (8-768)

xFrac_(C)=refy _(C) & 31  (8-769)

yFrac_(C)=refy _(C) & 31  (8-770)

-   -   The prediction sample value predSamplesLX[xC][yC] is derived by        invoking the process specified in clause 8.5.6.3.4 with        (xInt_(C), yInt_(C)), (xFrac_(C), yFrac_(C)), (xSbIntC,        ySbIntC), sbWidth, sbHeight and refPicLX as inputs.

Luma Sample Interpolation Filtering Process

Inputs to this process are:

-   -   a luma location in full-sample units (xInt_(L), yInt_(L)),    -   a luma location in fractional-sample units (xFrac_(L),        yFrac_(L)),    -   a luma location in full-sample units (xSbInt_(L), ySbInt_(L))        specifying the top-left sample of the bounding block for        reference sample padding relative to the top-left luma sample of        the reference picture,    -   the luma reference sample array refPicLX_(L),    -   the half sample interpolation filter index hpelIfIdx,    -   a variable sbWidth specifying the width of the current subblock,    -   a variable sbHeight specifying the height of the current        subblock,    -   a luma location (xSb, ySb) specifying the top-left sample of the        current subblock relative to the top-left luma sample of the        current picture,        Output of this process is a predicted luma sample value        predSampleLX_(L)        The variables shift1, shift2 and shift3 are derived as follows:    -   The variable shift1 is set equal to Min(4, BitDepth_(Y)−8), the        variable shift2 is set equal to 6 and the variable shift3 is set        equal to Max(2, 14−BitDepth_(Y)).    -   The variable picW is set equal to pic_width_in_luma_samples and        the variable picH is set equal to pic_height_in_luma_samples.        The luma interpolation filter coefficients f_(L)[p] for each        1/16 fractional sample position p equal to xFrac_(L), or        yFrac_(L) are derived as follows:    -   If MotionModelIdc[xSb][ySb] is greater than 0, and sbWidth and        sbHeight are both equal to 4, the luma interpolation filter        coefficients fL[p] are specified in Table 8-12.    -   Otherwise, the luma interpolation filter coefficients f_(L)[p]        are specified in Table 8-11 depending on hpelIfIdx.        The luma locations in full-sample units (xInt_(i), yInt_(i)) are        derived as follows for i=0 . . . 7:    -   If subpic_treated_as_pic_flag[SubPicIdx] is equal to 1, the        following applies:

xInt_(i)=Clip3(SubPicLeftBoundaryPos,SubPicRightBoundaryPos,xInt_(L)+i−3)  (8-771)

yInt_(i)=Clip3(SubPicTopBoundaryPos,SubPicBotBoundaryPos,y Int_(L)+i−3)  (8-772)

-   -   Otherwise (subpic_treated_as_pic_flag[SubPicIdx] is equal to 0),        the following applies:

xInt_(i)=Clip3(0,picW−1,sps_ref_wraparound_enabled_flag?ClipH((sps_ref_wraparound_offset_minus1+1)*MinCbSizeY,picW,xInt_(L)+i−3):xInt_(L) +i−3)   (8-773)

yInt_(i)=Clip3(0,picH−1,yInt_(L) +i−3)  (8-774)

The luma locations in full-sample units are further modified as followsfor i=0 . . . 7:

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))  (8-775)

yInt_(i)=Clip3(ySbInt_(L)−3,ySbInt_(L)+sbHeight+4,yInt_(i))  (8-776)

The predicted luma sample value predSampleLX_(L) is derived as follows:

-   -   If both xFrac_(L) and yFrac_(L) are equal to 0, the value of        predSampleLX_(L) is derived as follows:

predSampleLX _(L)=rePicLX _(L)[xInt3][yInt3]<<shift3  (8-777)

-   -   Otherwise, if xFrac_(L) is not equal to 0 and yFrac_(L) is equal        to 0, the value of predSampleLX_(L) is derived as follows:

predSampleLX _(L)=(Σ_(i=0) ⁷ f _(L)[xFrac_(L)][i]*refPicLX_(L)[xInt_(i)][yInt₃])>>shift1  (8-778)

-   -   Otherwise, if xFrac_(L) is equal to 0 and yFrac_(L) is not equal        to 0, the value of predSampleLX_(L) is derived as follows:

predSampleLX _(L)=(Σ_(i=0) ⁷ f _(L)[yFrac_(L)][i]*refPicLX_(L)[xInt₃][yInt_(i)])>>shift1  (8-779)

-   -   Otherwise, if xFrac_(L) is not equal to 0 and yFrac_(L) is not        equal to 0, the value of predSampleLX_(L) is derived as follows:        -   The sample array temp[n] with n=0 . . . 7, is derived as            follows:

temp[n]=(Σ_(i=0) ⁷ f _(L)[xFrac_(L)][i]*refPicLX_(L)[xInt_(i)][yInt_(n)])>>shift1  (8-780)

-   -   The predicted luma sample value predSampleLX_(L) is derived as        follows:

predSampleLX _(L)=(Σ_(i=0) ⁷ f_(L)[yFrac_(L)][i]*temp[i])>>shift2  (8-781)

TABLE 8-11 Specification of the luma interpolation filter coefficientsf_(L)[ p ] for each 1/16 fractional sample position p. Fractional sampleinterpolation filter coefficients position p f_(L)[ p ][ 0 ] f_(L)[ p ][1 ] f_(L)[ p ][ 2 ] f_(L)[ p ][ 3 ] f_(L)[ p ][ 4 ] f_(L)[ p ][ 5 ]f_(L)[ p ][ 6 ] f_(L)[ p ][ 7 ] 1 0 1 −3 63 4 −2 1 0 2 −1 2 −5 62 8 −3 10 3 −1 3 −8 60 13 −4 1 0 4 −1 4 −10 58 17 −5 1 0 5 −1 4 −11 52 26 −8 3−1 6 −1 3 −9 47 31 −10 4 −1 7 −1 4 −11 45 34 −10 4 −1 8 −1 4 −11 40 40−11 4 −1 (hpelIfIdx = = 0) 8 0 3 9 20 20 9 3 0 (hpelIfIdx = = 1) 9 −1 4−10 34 45 −11 4 −1 10  −1 4 −10 31 47 −9 3 −1 11  −1 3 −8 26 52 −11 4 −112  0 1 −5 17 58 −10 4 −1 13  0 1 −4 13 60 −8 3 −1 14  0 1 −3 8 62 −5 2−1 15  0 1 −2 4 63 −3 1 0

TABLE 8-12 Specification ofthe luma interpolation filter coefficientsf_(L)[ p ] for each 1/16 fractional sample position p for affine motionmode. Fractional interpolation filter coefficients sample position pf_(L)[ p ][ 0 ] f_(L)[ p ][ 1 ] f_(L)[ p ][ 2 ] f_(L)[ p ][ 3 ] f_(L)[ p][ 4 ] f_(L)[ p ][ 5 ] f_(L)[ p ][ 6 ] f_(L)[ p ][ 7 ] 1 0 1 −3 63 4 −21 0 2 0 1 −5 62 8 −3 1 0 3 0 2 −8 60 13 −4 1 0 4 0 3 −10 58 17 −5 1 0 50 3 −11 52 26 −8 2 0 6 0 2 −9 47 31 −10 3 0 7 0 3 −11 45 34 −10 3 0 8 03 −11 40 40 −11 3 0 9 0 3 −10 34 45 −11 3 0 10 0 3 −10 31 47 −9 2 0 11 02 −8 26 52 −11 3 0 12 0 1 −5 17 58 −10 3 0 13 0 1 −4 13 60 −8 2 0 14 0 1−3 8 62 −5 1 0 15 0 1 −2 4 63 −3 1 0

Luma Integer Sample Fetching Process

Inputs to this process are:

-   -   a luma location in full-sample units (xInt_(L), yInt_(L)),    -   the luma reference sample array refPicLX_(L),        Output of this process is a predicted luma sample value        predSampleLX_(L)        The variable shift is set equal to Max(2, 14−BitDepth_(Y)).        The variable picW is set equal to pic_width_in_luma_samples and        the variable picH is set equal to pic_height_in_luma_samples.        The luma locations in full-sample units (xInt, yInt) are derived        as follows:

xInt=Clip3(0,picW−1,sps_ref_wraparound_enabled_flag?ClipH((sps_ref_wraparound_offset_minus1+1)*MinCbSizeY,picW,xInt_(L)):xInt_(L))  (8-782)

yInt=Clip3(0,picH−1,yInt_(L))  (8-783)

The predicted luma sample value predSampleLX_(L) is derived as follows:

predSampleLX _(L)=refPicLX[xInt][yInt]<<shift3   (8-784)

Chroma Sample Interpolation Process

Inputs to this process are:

-   -   a chroma location in full-sample units (xInt_(C), yInt_(C)),    -   a chroma location in 1/32 fractional-sample units (xFrac_(C),        yFrac_(C)),    -   a chroma location in full-sample units (xSbIntC, ySbIntC)        specifying the top-left sample of the bounding block for        reference sample padding relative to the top-left chroma sample        of the reference picture,    -   a variable sbWidth specifying the width of the current subblock,    -   a variable sbHeight specifying the height of the current        subblock,    -   the chroma reference sample array refPicLX_(C).        Output of this process is a predicted chroma sample value        predSampleLX_(C)        The variables shift1, shift2 and shift3 are derived as follows:    -   The variable shift1 is set equal to Min(4, BitDepth_(C)−8), the        variable shift2 is set equal to 6 and the variable shift3 is set        equal to Max(2, 14−BitDepth_(C)).    -   The variable picW_(C) is set equal to        pic_width_in_luma_samples/SubWidthC and the variable picH_(C) is        set equal to pic_height_in_luma_samples/SubHeightC.        The chroma interpolation filter coefficients f_(C)[p] for each        1/32 fractional sample position p equal to xFrac_(C) or        yFrac_(C) are specified in Table 8-13.        The variable xOffset is set equal to

(sps_ref_wraparound_offset_minus1+1)*MinCbSizeY)/SubWidthC.

The chroma locations in full-sample units (xInt_(i), yInt_(i)) arederived as follows for i=0 . . . 3:

-   -   If subpic_treated_as_pic_flag[SubPicIdx] is equal to 1, the        following applies:

xInt_(i)=Clip3(SubPicLeftBoundaryPos/SubWidthC,SubPicRightBoundaryPos/SubWidthC,xInt_(L)+i)  (8-785)

yInt_(i)=Clip3(SubPicTopBoundaryPos/SubHeightC,SubPicBotBoundaryPos/SubHeightC,yInt_(L)+i)  (8-786)

-   -   Otherwise (subpic_treated_as_pic_flag[SubPicIdx] is equal to 0),        the following applies:

xInt_(i)=Clip3(0,picW_(C)−1,sps_ref_wraparound_enabled_flag?ClipH(xOffset,picW _(C) ,xInt_(C)+i−1):xInt_(C) +i−1)   (8-787)

yInt_(i)=Clip3(0,picH _(C)−1,yInt_(C) +i−1)  (8-788)

The chroma locations in full-sample units (xInt_(i), yInt_(i)) arefurther modified as follows for i=0 . . . 3:

xInt_(i)=Clip3(xSbIntC−1,xSbIntC+sbWidth+2,xInt_(i))  (8-789)

yInt_(i)=Clip3(ySbIntC−1,ySbIntC+sbHeight+2,yInt_(i))  (8-790)

The predicted chroma sample value predSampleLX_(C) is derived asfollows:

-   -   If both xFrac_(C) and yFrac_(C) are equal to 0, the value of        predSampleLX_(C) is derived as follows:

predSampleLX _(C)=refPicLX _(C)[xInt₁][yInt₁]<<shift3  (8-791)

-   -   Otherwise, if xFrac_(C) is not equal to 0 and yFrac_(C) is equal        to 0, the value of predSampleLX_(C) is derived as follows:

predSampleLX _(C)=(Σ_(i=0) ³ f _(C)[xFrac_(C)][i]*refPicLX_(C)[xInt_(i)][yInt₁])>>shift1  (8-792)

-   -   Otherwise, if xFrac_(C) is equal to 0 and yFrac_(C) is not equal        to 0, the value of predSampleLX_(C) is derived as follows:

predSampleLX _(C)=(Σ_(i=0) ³ f _(C)[yFrac_(C)][i]*refPicLX_(C)[xInt₁][yInt_(i)])>>shift1  (8-793)

-   -   Otherwise, if xFrac_(C) is not equal to 0 and yFrac_(C) is not        equal to 0, the value of predSampleLX_(C) is derived as follows:        -   The sample array temp[n] with n=0 . . . 3, is derived as            follows:

temp[n]=(Σ_(i=0) ³ f _(C)[xFrac_(C)][i]*refPicLX_(C)[xInt_(i)][yInt_(n)])>>shift1  (8-794)

-   -   -   The predicted chroma sample value predSampleLX_(C) is            derived as follows:

predSampleLX _(C)=(f _(C)[yFrac_(C)][0]*temp[0]+f_(C)[yFrac_(C)][1]*temp[1]+f _(C)[yFrac_(C)][2]*temp[2]+f_(C)[yFrac_(C)][3]*temp[3])>>shift2   (8-795)

TABLE 8-13 Specification of the chroma interpolation filter coefficientsf_(C)[p] for each 1/32 fractional sample position p. Fractional sampleinterpolation filter coefficients position p f_(C)[p][0] f_(C)[p][1]f_(C)[p][2] f_(C)[p][3] 1 −1 63 2 0 2 −2 62 4 0 3 -2 60 7 −1 4 −2 58 10−2 5 −3 57 12 −2 6 −4 56 14 −2 7 −4 55 15 −2 8 −4 54 16 −2 9 −5 53 18 −210 −6 52 20 −2 11 −6 49 24 −3 12 −6 46 28 −4 13 −5 44 29 −4 14 −4 42 30−4 15 −4 39 33 −4 16 −4 36 36 −4 17 −4 33 39 −4 18 −4 30 42 −4 19 −4 2944 −5 20 −4 28 46 −6 21 −3 24 49 −6 22 −2 20 52 −6 23 −2 18 53 −5 24 −216 54 −4 25 −2 15 55 −4 26 −2 14 56 −4 27 −2 12 57 −3 28 −2 10 58 −2 29−1 7 60 −2 30 0 4 62 −2 31 0 2 63 −1 31 0 2 63 −1

2.4. Wrap-Around Clipping in VVC

Wrap-around clipping was proposed JVET-L0231 to address the ERP or PERPpicture format as shown in FIG. 5. This is also sometimes calledreference picture wrapping.

In JVET-P2001-v9, wrap-around clipping is specified that

${{ClipH}( {o,W,x} )} = \{ \begin{matrix}{{x + o};} & {x < 0} \\{{x - o};} & {x > {W - 1}} \\{x;} & {otherwise}\end{matrix} $

And a horizontal position will be clipped depending on whetherwraparound clipping is applied. In JVET-P2001-v9, it is specified as:

The luma locations in full-sample units (xInt_(i), yInt_(i)) are derivedas follows for i=0 . . . 7:

-   -   If subpic_treated_as_pic_flag[SubPicIdx] is equal to 1, the        following applies:

xInt_(i)=Clip3(SubPicLeftBoundaryPos,SubPicRightBoundaryPos,xInt_(L)+i−3)  (8-754)

yInt_(i)=Clip3(SubPicTopBoundaryPos,SubPicBotBoundaryPos,yInt_(L)+i−3)  (8-755)

-   -   Otherwise (subpic_treated_as_pic_flag[SubPicIdx] is equal to 0),        the following applies:

xInt_(i)=Clip3(0,picW−1,sps_ref_wraparound_enabled_flag?ClipH((sps_ref_wraparound_offset_minus1+1)*MinCbSizeY,picW,xInt_(L)+i−3):xInt_(L) +i−3)   (8-756)

yInt_(i)=Clip3(0,picH−1,yInt_(L) +i−3)  (8-757)

2.5. CCLM in VVC

Parameters are derived for Cross-Component Linear Model (CCLM)prediction in VVC as specified in JVET-P2001-v9:

8.4.5.2.13 Specification of INTRA_LT_CCLM, INTRA_L_CCLM and INTRA_T_CCLMintra prediction mode

-   -   . . .

7. The variables a, b, and k are derived as follows:

-   -   If numSampL is equal to 0, and numSampT is equal to 0, the        following applies:

k=0  (8-211)

a=0  (8-212)

b=1<<(BitDepth−1)  (8-213)

-   -   -   Otherwise, the following applies:

diff=maxY−minY  (8-214)

-   -   -   -   If diff is not equal to 0, the following applies:

diffC=maxC−minC  (8-215)

x=Floor(Log 2(diff))  (8-216)

normDiff=((diff>>4)>>x)&15  (8-217)

x+=(normDiff!=0)?1:0  (8-218)

y=Floor(Log 2(Abs(diffC)))+1  (8-219)

a=(diffC*(divSigTable[normDiff]|8)+2^(v)−1)>>y  (8-220)

k=((3+x−y)<1)?1:3+x−y  (8-221)

a=((3+x−y)<1)?Sign(a)*15:a  (8-222)

b=minC−((a*minY)>>k)  (8-223)

-   -   -   -   -   where divSigTable[ ] is specified as follows:

divSigTable[ ]={0,7,6,5,5,4,4,3,3,2,2,1,1,1,1,0}  (8-224)

-   -   -   -   Otherwise (diff is equal to 0), the following applies:

k=0  (8-225)

a=0  (8-226)

b=minC  (8-227)

2.6. Angular Prediction in VVC

Angular prediction in VVC is specified in JVET-P2001-v9 as:

-   -   8.4.5.2.12 Specification of INTRA_ANGULAR2 . . . INTRA_ANGULAR66        intra prediction modes        Inputs to this process are:    -   the intra prediction mode predModeIntra,    -   a variable refIdx specifying the intra prediction reference line        index,    -   a variable nTbW specifying the transform block width,    -   a variable nTbH specifying the transform block height,    -   a variable refW specifying the reference samples width,    -   a variable refH specifying the reference samples height,    -   a variable nCbW specifying the coding block width,    -   a variable nCbH specifying the coding block height,    -   a variable refFilterFlag specifying the value of reference        filter flag,    -   a variable cIdx specifying the colour component of the current        block,    -   the neighbouring samples p[x][y], with x=−1−refIdx, y=−1−refIdx        . . . refH−1 and x=−refIdx . . . refW−1, y=−1−refIdx.        Outputs of this process are the predicted samples        predSamples[x][y], with x=0 . . . nTbW−1, y=0 . . . nTbH−1.        The variable nTbS is set equal to (Log 2 (nTbW)+Log 2(nTbH))>>1.        The variable filterFlag is derived as follows:    -   If one or more of the following conditions is true, filterFag is        set equal to 0.        -   refFilterFlag is equal to 1        -   refIdx is not equal to 0        -   IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT    -   Otherwise, the following applies:        -   The variable minDistVerHor is set equal to            Min(Abs(predModeIntra−50), Abs(predModeIntra−18)).        -   The variable intraHorVerDistThres[nTbS] is specified in            Table 8-7.        -   The variable filterFlag is derived as follows:            -   If minDistVerHor is greater than                intraHorVerDistThres[nTbS] and refFilterFlag is equal to                0, filterFlag is set equal to 1.            -   Otherwise, filterFlag is set equal to 0.

TABLE 8-7 Specification of intraHorVerDistThres[ nTbS ] for varioustransform block sizes nTbS nTbS = 2 nTbS = 3 nTbS = 4 nTbS = 5 nTbS = 6nTbS = 7 intraHorVerDistThres[ nTbS ] 24 14 2 0 0 0Table 8-8 specifies the mapping table between predModeIntra and theangle parameter intraPredAngle.

TABLE 8-8 Specification of intraPredAngle predModeIntra −14 −13 −12 −11−10 −9 −8 −7 −6 −5 −4 −3 −2 −1 2 3 4 intraPredAngle 512 341 256 171 128102 86 73 64 57 51 45 39 35 32 29 26 predModeIntra 5 6 7 8 9 10 11 12 1314 15 16 17 18 19 20 21 intraPredAngle 23 20 18 16 14 12 10 8 6 4 3 2 10 −1 −2 −3 predModeIntra 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 3738 intraPredAngle −4 −6 −8 −10 −12 −14 −16 −18 −20 −23 −26 −29 −32 −29−26 −23 −20 predModeIntra 39 40 41 42 43 44 45 46 47 48 49 50 51 52 5354 55 intraPredAngle −18 −16 −14 −12 −10 −8 −6 −4 −3 −2 −1 0 1 2 3 4 6predModeIntra 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72intraPredAngle 8 10 12 14 16 18 20 23 26 29 32 35 39 45 51 57 64predModeIntra 73 74 75 76 77 78 79 80 intraPredAngle 73 86 102 128 171256 341 512The inverse angle parameter invAngle is derived based on intraPredAngleas follows:

$\begin{matrix}{{{invAngle} = {{{Round}( \frac{512*32}{intraPredAngle} )}.\;.\;.}}\;} & \text{(8-129)}\end{matrix}$

2.7. Sample Fetching for Inter-Prediction in VVC 8.5.6.3.2 Luma SampleInterpolation Filtering Process

-   -   . . .        The luma locations in full-sample units (xInt_(i), yInt_(i)) are        derived as follows for i=0 . . . 7:    -   If subpic_treated_as_pic_flag[SubPicIdx] is equal to 1, the        following applies:

xInt_(i)=Clip3(SubPicLeftBoundaryPos,SubPicRightBoundaryPos,xInt_(L)+i−3)  (8-754)

yInt_(i)=Clip3(SubPicTopBoundaryPos,SubPicBotBoundaryPos,yInt_(L)+i−3)  (8-755)

-   -   Otherwise (subpic_treated_as_pic_flag[SubPicIdx] is equal to 0),        the following applies:

xInt_(i)=Clip3(0,picW−1,sps_ref_wraparound_enabled_flag?ClipH((sps_ref_wraparound_offset_minus1+1)*MinCbSizeY,picW,xInt_(L)+i−3):xInt_(L) +i−3)

yInt_(i)=Clip3(0,picH−1,yInt_(L) +i−3)

The luma locations in full-sample units are further modified as followsfor i=0 . . . 7:

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))

yInt_(i)=Clip3(ySbInt_(L)−3,ySbInt_(L)+sbHeight+4,yInt_(i))

The predicted luma sample value predSampleLX_(L) is derived as follows:

-   -   If both xFrac_(L) and yFrac_(L) are equal to 0, and both        hori_scale_fp and vert_scale_fp are less than 20481, the value        of predSampleLX_(L) is derived as follows:

predSampleLX _(L)=refPicLX _(L)[xInt₃][yInt₃]<<shift3

. . .

8.5.6.3.4 Chroma Sample Interpolation Process

. . .

The chroma locations in full-sample units (xInt_(i), yInt_(i)) arefurther modified as follows for i=0 . . . 3:

xInt_(i)=Clip3(xSbIntC−1,xSbIntC+sbWidth+2,xInt_(i))  (8-774)

yInt_(i)=Clip3(ySbIntC−1,ySbIntC+sbHeight+2,yInt_(i))  (8-775)

2.8. Subpicture

In VVC, the concept of subpictures is introduced. A subpicture is arectangular region of one or more slices within a picture. For a videosequence, multiple subpictures may be used. And all pictures are splitto same number of subpictures which are defined in SPS.

The related syntax elements and semantics are defined as follows:

7.3.2.3 Sequence parameter set RBSP syntax Descriptorseq_parameter_set_rbsp( ){  sps_decoding_parameter_set_id u(4) sps_video_parameter_set_id u(4)  sps_max_sublayers_minus1 u(3) sps_reserved_zero_4bits u(4)  sps_ptl_dpb_hrd_params_present_flag u(1) if( sps_ptl_dpb_hrd_params_present_flag)   profile_tier_level( 1,sps_max_sublayers_minus1)  gdr_enabled_flag u(1) sps_seq_parameter_set_id u(4)  chroma_format_idc u(2)  if(chroma_format_idc == 3)   separate_colour_plane_flag u(1) ref_pic_resampling_enabled_flag u(1)  pic_width_max_in_luma_samplesue(v)  pic_height_max_in_luma_samples ue(v)  sps_log2_ctu_size_minus5u(2)  subpics_present_flag u(1)  if(subpics_present _flag ) {  sps_num_subpics_minus1 u(8)   for(i = 0; i <= sps_num_subpics minus1;i++) {    subpic_ctu_top_left_x[i] u(v)    subpic_ctu_top_left_y[i] u(v)   subpic_width_minus1[i] u(v)    subpic_height_minus1[i] u(v)   subpic_treated as_pic_flag[i] u(1)   loop_filter_across_subpic_enabled_flag[i] u(1)   }  } sps_subpic_id_present_flag u(1)  if(sps_subpics_id_present_flag){  sps_subpic_id_signalling_present_flag{  if(sps_subpics_id_signalling_present_flag){   sps_subpic_id_len_minus1 ue(v)    for(i = 0; i <=sps_num_subpics_minus1;++)     sps_subpic_id[i] u(v)   }  } bit_depth_minus8 ue(v) ... }subpics_present_flag equal to 1 specifies that subpicture parameters arepresent in in the SPS RBSP syntax. subpics_present_flag equal to 0specifies that subpicture parameters are not present in the SPS RBSPsyntax.

-   -   NOTE 2—When a bitstream is the result of a sub-bitstream        extraction process and contains only a subset of the subpictures        of the input bitstream to the sub-bitstream extraction process,        it might be required to set the value of subpics_present_flag        equal to 1 in the RBSP of the SPSs.        sps_num_subpics_minus1 plus 1 specifies the number of        subpictures. sps_num_subpics_minus1 shall be in the range of 0        to 254. When not present, the value of sps_num_subpics_minus1 is        inferred to be equal to 0.        subpic_ctu_top_left_x[i] specifies horizontal position of top        left CTU of i-th subpicture in unit of CtbSizeY. The length of        the syntax element is Ceil(Log        2(pic_width_max_in_luma_samples/CtbSizeY)) bits. When not        present, the value of subpic_ctu_top_left_x[i] is inferred to be        equal to 0.        subpic_ctu_top_left_y[i] specifies vertical position of top left        CTU of i-th subpicture in unit of CtbSizeY. The length of the        syntax element is Ceil(Log        2(pic_height_max_in_luma_samples/CtbSizeY)) bits. When not        present, the value of subpic_ctu_top_left_y[i] is inferred to be        equal to 0.        subpic_width_minus1[i] plus 1 specifies the width of the i-th        subpicture in units of CtbSizeY. The length of the syntax        element is Ceil(Log 2(pic_width_max_in_luma_samples/CtbSizeY))        bits. When not present, the value of subpic_width_minus1[i] is        inferred to be equal to        Ceil(pic_width_max_in_luma_samples/CtbSizeY)−1.        subpic_height_minus1[i] plus 1 specifies the height of the i-th        subpicture in units of CtbSizeY. The length of the syntax        element is Ceil(Log 2(pic_height_max_in_luma_samples/CtbSizeY))        bits. When not present, the value of subpic_height_minus1[i] is        inferred to be equal to        Ceil(pic_height_max_in_luma_samples/CtbSizeY)−1.        subpic_treated_as_pic_flag[i] equal to 1 specifies that the i-th        subpicture of each coded picture in the CLVS is treated as a        picture in the decoding process excluding in-loop filtering        operations subpic_treated_as_pic_flag[i] equal to 0 specifies        that the i-th subpicture of each coded picture in the CLVS is        not treated as a picture in the decoding process excluding        in-loop filtering operations. When not present, the value of        subpic_treated_as_pic_flag[i] is inferred to be equal to 0.        loop_filter_across_subpic_enabled_flag[i] equal to 1 specifies        that in-loop filtering operations may be performed across the        boundaries of the i-th subpicture in each coded picture in the        CLVS. loop_filter_across_subpic_enabled_flag[i] equal to 0        specifies that in-loop filtering operations are not performed        across the boundaries of the i-th subpicture in each coded        picture in the CLVS. When not present, the value of        loop_filter_across_subpic_enabled_pic_flag[i] is inferred to be        equal to 1.        It is a requirement of bitstream conformance that the following        constraints apply:    -   For any two subpictures subpicA and subpicB, when the subpicture        index of subpicA is less than that of subpicB, any coded slice        NAL unit of subPicA shall precede any coded slice NAL unit of        subPicB in decoding order.    -   The shapes of the subpictures shall be such that each        subpicture, when decoded, shall have its entire left boundary        and entire top boundary consisting of picture boundaries or        consisting of boundaries of previously decoded subpictures.        sps_subpic_id_prsent_flag equal to 1 specifies that subpicture        ID mapping is present in the SPS. sps_subpic_id_present_flag        equal to 0 specifies that subpicture ID mapping is not present        in the SPS.        sps_subpic_id_signalling_present_flag equal to 1 specifies that        subpicture ID mapping is signalled in the SPS.        sps_subpic_id_signalling_present_flag equal to 0 specifies that        subpicture ID mapping is not signalled in the SPS. When not        present, the value of sps_subpic_id_signalling_present_flag is        inferred to be equal to 0.        sps_subpic_id_len_minus1 plus 1 specifies the number of bits        used to represent the syntax element sps_subpic_id[i]. The value        of sps_subpic_id_len_minus1 shall be in the range of 0 to 15,        inclusive.        sps_subpic_id[i] specifies that subpicture ID of the i-th        subpicture. The length of the sps_subpic_id[i] syntax element is        sps_subpic_id_len_minus1+1 bits. When not present, and when        sps_subpic_id_present_flag equal to 0, the value of        sps_subpic_id[i] is inferred to be equal to i, for each i in the        range of 0 to sps_num_subpics_minus1, inclusive

7.3.2.4 Picture Parameter Set RBSP Syntax

De- scrip- tor pic_parameter_set_rbsp( ) {  pps_pic_parameter_set_idue(v)  pps_seq_parameter_set_id u(4)  pic_width_in_luma_samples ue(v) pic_height_in_luma_samples ue(v) ...  output_flag_present_flag u(1) mixed_nalu_types_in_pic_flag u(1) pps_subpic_id_signalling_present_flag u(1) if(pps_subpics_id_signalling_present_flag) {   pps_num_subpics_minus1ue(v)   pps_subpic_id_len_minus1 ue(v)   for(i = 0; i <=pps_num_subpic_minus1;++)    pps_subpic_id[i] u(v)  } no_pic_partition_flag u(1)  if( !no_pic_partition_flag) {  pps_1og2_ctu_size_minus5 u(2)   num_exp_tile_columns_minus1 ue(v)  num_exp_tile_rows_minus1 ue(v)   for( i =0; i <= num_exp_tile_columns_minus1; i++)    tile_colum_width_minus1[i] ue(v)  for( i =0; i <= num _exp_tile_rows_minus1; i++)   tile_row_height_minus1[i] ue(v)   rect_slice_flag u(1)  if(rect_slice_flag)    single slice_per_subpic_flag u(1)  if(rect_slice _flag && !single_slice_per_subpic_flag){   num_slices_in_pic_minus1 ue(v)    tile_idx_delta_present_flag u(1)   for( i =0; i < num_slices_in_pic_minus1; i++) {    slice_width_in_tiles_minus[i] ue(v)    slice_height_in_tiles_minus[i] ue(v)     if(slice_width_in_tiles_minus1[i] == 0 &&     slice_height_in_tiles_minus1[i] == 0) {    num_slices_in_tile_minus1[i] ue(v)     num SlicesInTileMinus1 = num_slices_in_tile_minus1[i]     for( j =0; j < num SlicesInTileMinus1 ;j++)      slice_height_in_ctu_minus1[i++] ue(v)     }     if(tile_idx_delta_present_flag && i <     num_slices_in_pic_minus1)     tile_idx_delta[i] se(v)    }   }  loop_filter_across_tiles_enabled_flag u(1)  loop_filter_across_slices_enabled_flag u(1)  } entropy_coding_sync_enabled_flag u(1) ... }single_slice_per_subpic_flag equal to 1 specifies that each subpictureconsists of one and only one rectangular slice.single_slice_per_subpic_flag equal to 0 specifies that each subpicturemay consist one or more rectangular slices. When subpics_present_flag isequal to 0, single_slice_per_subpic_flag shall be equal to 0. Whensingle_slice_per_subpic_flag is equal to 1, num_slices_in_pic_minus1 isinferred to be equal to sps_num_subpics_minus1.

7.3.7.1 General Slice Header Syntax

Descriptor slice_header( ) {  slice_pic_order_cnt_lsb u(v)  if(subpics_present _flag )   slice_subpic_id u(v)  if( rect_slice_flag ||Num TilesInPic > 1)   slice_address u(v) ... }slice_subpic_id specifies the subpicture identifier of the subpicturethat contains the slice. If slice_subpic_id is present, the value of thevariable SubPicIdx is derived to be such that SubpicIdList[SubPicIdx] isequal to slice_subpic_id. Otherwise (slice_subpic_id is not present),the variable SubPicIdx is derived to be equal to 0. The length ofslice_subpic_id, in bits, is derived as follows:

-   -   If sps_subpic_id_signalling_present_flag is equal to 1, the        length of slice_subpic_id is equal to        sps_subpic_id_len_minus1+1.    -   Otherwise, if ph_subpic_id_signalling_present_flag is equal to        1, the length of slice_subpic_id is equal to        ph_subpic_id_len_minus1+1.    -   Otherwise, if pps_subpic_id_signalling_present_flag is equal to        1, the length of slice_subpic_id is equal to        pps_subpic_id_len_minus1+1.    -   Otherwise, the length of slice_subpic_id is equal to Ceil(Log 2        (sps_num_subpics_minus1+1)).

3. Technical Problems Addressed by Technical Solutions Disclosed Herein

When RPR is applied in VVC, RPR (ARC) may have the following problems:

-   -   1. With RPR, the interpolation filters may be different for        adjacent samples in a block, which is undesirable in SIMD        (Single Instruction Multiple Data) implementation.    -   2. The bounding region does not consider RPR.    -   3. Wrap-around offset (sps_ref_wraparound_offset_minus1) is        signaled in sequence level, but the dimensions of pictures may        vary due to RPR in the sequence.    -   4. Abs (diffC) may be equal to 0 in Log 2(Abs(diffC)) to derive        parameters for CCLM.    -   5. intraPredAngle may be 0, making invAngle meaningless.    -   6. The highlighted clipping operation described in section 2.7        (denoted as “the integer sample clipping operation”) may damage        the motion compensation for RPR.    -   7. In current VVC, the intra (I) slice is defined as a slice        that is decoded using intra prediction only. However, due to the        recent adoption of IBC and palette mode coding as additional        prediction modes besides the intra and inter prediction, for I        slices, in addition to intra prediction, the IBC/palette modes        could also be applied. Such a definition needs to be revised        accordingly.    -   8. Indications of subpictures are defined in VVC wherein a        subpics_present_flag is firstly signaled, followed by        sps_num_subpics_minus1. However, it is noticed that even        subpicture present flag is true, the signaled        sps_num_subpics_minus1 could still be equal to 0 meaning only        one subpicture within one picture, i.e., subpicture is equal to        picture; and when subpicture present flag is false, the        sps_num_subpics_minus1 is also inferred to be 0. Therefore, it        is not reasonable to define the range of sps_num_subpics_minus1        is from 0 to 254, inclusive, when it is signalled.

4. A Listing of Embodiments and Techniques

The list below should be considered as examples to explain generalconcepts. These items should not be interpreted in a narrow way.Furthermore, these items can be combined in any manner.

A motion vector is denoted by (mv_x, mv_y) wherein mv_x is thehorizontal component and mv_y is the vertical component.

RPR Related

-   -   1. When the resolution of the reference picture is different to        the current picture, predicted values for a group of samples (at        least two samples) of a current block may be generated with the        same horizontal and/or vertical interpolation filter.        -   a. In one example, the group may comprise all samples in a            region of the block.            -   i. For example, a block may be divided into S M×N                rectangles not overlapped with each other. Each M×N                rectangle is a group. In an example as shown in FIG. 1,                a 16×16 block can be divided into 16 4×4 rectangles,                each of which is a group.            -   ii. For example, a row with N samples is a group. Nis an                integer no larger than the block width. In one example,                N is 4 or 8 or the block width.            -   iii. For example, a column with N samples is a group. N                is an integer no larger than the block height. In one                example, N is 4 or 8 or the block height.            -   iv. M and/or N may be pre-defined or derived on-the-fly,                such as based on block dimension/coded information or                signaled.        -   b. In one example, samples in the group may have the same MV            (denoted as shared MV).        -   c. In one example, samples in the group may have MVs with            the same horizontal component (denoted as shared horizontal            component).        -   d. In one example, samples in the group may have MVs with            the same vertical component (denoted as shared vertical            component).        -   e. In one example, samples in the group may have MVs with            the same fractional part of the horizontal component            (denoted as shared fractional horizontal component).            -   i. For example, suppose the MV for a first sample is                (MV1x, MV1y) and the MV for a second sample is (MV2x,                MV2y), it should be satisfied that MV1x & (2^(M)−1) is                equal to MV2x & (2^(M)−1), where M denotes MV precision.                For example, M=4.        -   f. In one example, samples in the group may have MVs with            the same fractional part of the vertical component (denoted            as shared fractional vertical component).            -   i. For example, suppose the MV for a first sample is                (MV1x, MV1y) and the MV for a second sample is (MV2x,                MV2y), it should be satisfied that MV1y & (2^(M)−1) is                equal to MV2y & (2^(M)−1), where M denotes MV precision.                For example, M=4.        -   g. In one example, for a sample in the group to be            predicted, the motion vector, denoted by MV_(b), may be            firstly derived according to the resolutions of the current            picture and the reference picture (e.g. (refx_(L), refy_(L))            derived in 8.5.6.3.1 in JVET-O2001-v14). Then, MV_(b) may be            further modified (e.g., being rounded/truncated/clipped) to            MV′ to satisfy the requirements such as the above bullets,            and MV′ will be used to derive the prediction sample for the            sample.            -   i. In one example, MV′ has the same integer part as                MV_(b), and the fractional part of the MV′ is set to be                the shared fractional horizontal and/or vertical                component.            -   ii. In one example, MV′ is set to be the one with the                shared fractional horizontal and/or vertical component,                and closest to MV_(b).        -   h. The shared motion vector (and/or shared horizontal            component and/or shared vertical component and/or shared            fractional vertical component and/or shared fractional            vertical component) may be set to be the motion vector            (and/or horizontal component and/or vertical component            and/or fractional vertical component and/or fractional            vertical component) of a specific sample in the group.            -   i. For example, the specific sample may be at a corner                of a rectangle-shaped group, such as “A”, “B’, “C” and                “D” shown in FIG. 2A.            -   ii. For example, the specific sample may be at a center                of a rectangle-shaped group, such as “E”, “F’, “G” and                “H” shown in FIG. 2A.            -   iii. For example, the specific sample may be at an end                of a row-shaped or column-shaped group, such as “A” and                “D” shown in FIGS. 2B and 2C.            -   iv. For example, the specific sample may be at a middle                of a row-shaped or column-shaped group, such as “B” and                “C” shown in FIGS. 2B and 2C.            -   v. In one example, the motion vector of the specific                sample may be the MV_(b) mentioned in bullet g.        -   i. The shared motion vector (and/or shared horizontal            component and/or shared vertical component and/or shared            fractional vertical component and/or shared fractional            vertical component) may be set to be the motion vector            (and/or horizontal component and/or vertical component            and/or fractional vertical component and/or fractional            vertical component) of a virtual sample located at a            different position compared to all samples in this group.            -   i. In one example, the virtual sample is not in the                group, but it locates in the region covering all samples                in the group.                -   1) Alternatively, the virtual sample is located                    outside the region covering all samples in the                    group, e.g., next to the bottom-right position of                    the region.            -   ii. In one example, the MV of a virtual sample is                derived in the same way as a real sample but with                different positions.            -   iii. “V” in FIGS. 2A-2C shows three examples of virtual                samples.        -   j. The shared MV (and/or shared horizontal component and/or            shared vertical component and/or shared fractional vertical            component and/or shared fractional vertical component) may            be set to be a function of MVs (and/or horizontal components            and/or vertical components and/or fractional vertical            components and/or fractional vertical components) of            multiple samples and/or virtual samples.            -   i. For example, the shared MV (and/or shared horizontal                component and/or shared vertical component and/or shared                fractional vertical component and/or shared fractional                vertical component) may be set to be the average of MVs                (and/or horizontal components and/or vertical components                and/or fractional vertical components and/or fractional                vertical components) of all or partial of samples in the                group, or of sample “E”, “F”, “G”, “H” in FIG. 2A, or of                sample “E”, “H” in FIG. 2A or of sample “A”, “B”, “C”,                “D” in FIG. 2A, or of sample “A”, “D” in FIG. 2A, or of                sample “B”, “C” in FIG. 2B, or of sample “A”, “D” in                FIG. 2B, or of sample “B”, “C” in FIG. 2C, or of sample                “A”, “D” in FIG. 2C.    -   2. It is proposed that only integer MVs are allowed to perform        the motion compensation process to derive the prediction block        of a current block when the resolution of the reference picture        is different to the current picture.        -   a. In one example, the decoded motion vectors for samples to            be predicted are rounded to integer MVs before being used.    -   3. The motion vectors used in the motion compensation process        for samples in a current block (e.g., shared MV/shared        horizontal or vertical or fractional component/MV′ mentioned in        above bullets) may be stored in the decoded picture buffer and        utilized for motion vector prediction of succeeding blocks in        current/different pictures.        -   a. Alternatively, the motion vectors used in the motion            compensation process for samples in a current block (e.g.,            shared MV/shared horizontal or vertical or fractional            component/MV′ mentioned in above bullets) may be disallowed            to be utilized for motion vector prediction of succeeding            blocks in current/different pictures.            -   i. In one example, the decoded motion vectors (e.g.,                MV_(b) in above bullets) may be utilized for motion                vector prediction of succeeding blocks in                current/different pictures.        -   b. In one example, the motion vectors used in the motion            compensation process for samples in a current block may be            utilized in the filtering process (e.g., deblocking            filter/SAO/ALF).            -   i. Alternatively, the decoded motion vectors (e.g.,                MV_(b) in above bullets) may be utilized in the                filtering process.    -   4. It is proposed that the interpolation filters used in the        motion compensation process to derive the prediction block of a        current block may be selected depending on whether the        resolution of the reference picture is different to the current        picture.        -   a. In one example, the interpolation filters have less taps            when the resolution of the reference picture is different to            the current picture.            -   i. In one example, bi-linear filters are applied when                the resolution of the reference picture is different to                the current picture.            -   ii. In one example, 4-tap filters or 6-tap filters are                applied when the resolution of the reference picture is                different to the current picture.    -   5. It is proposed that a two-stage process for prediction block        generation is applied when the resolution of the reference        picture is different to the current picture.        -   a. In the first stage, a virtual reference block is            generated by up-sampling or downsampling a region in the            reference picture depending on width and/or height of the            current picture and the reference picture.        -   b. In the second stage, the prediction samples are generated            from the virtual reference block by applying interpolation            filtering, independent of width and/or height of the current            picture and the reference picture.    -   6. It is proposed that the calculation of top-left coordinate of        the bounding block for reference sample padding (xSbInt_(L),        ySbInt_(L)) as defined in 8.5.6.3.1 in JVET-O2001-v14 may be        derived depending on width and/or height of the current picture        and the reference picture.        -   a. In one example, the luma locations in full-sample units            are modified as:

xInt_(i)=Clip3(xSbInt_(L) −Dx,xSbInt_(L)+sbWidth+Ux,xInt_(i)),

yInt_(i)=Clip3(ySbInt_(L) −Dy,ySbInt_(L)+sbHeight+Uy,yInt_(i)),

-   -   -   -   where Dx and/or Dy and/or Ux and/or Uy may depend on                width and/or height of the current picture and the                reference picture.

        -   b. In one example, the chroma locations in full-sample units            are modified as:

xInti=Clip3(xSbInt_(C) −Dx,xSbInt_(C)+sbWidth+Ux,xInti)

yInti=Clip3(ySbInt_(C) −Dy,ySbInt_(C)+sbHeight+Uy,yInti)

-   -   -   -   where Dx and/or Dy and/or Ux and/or Uy may depend on                width and/or height of the current picture and the                reference picture.

    -   7. It is proposed that whether to and/or how to clip MV        according to the bounding block for reference sample padding        (e.g., the (xSbInt_(L), ySbInt_(L)) as defined in 8.5.6.3.1 in        JVET-O2001-v14) may depend on the usage of DMVR.        -   a. In one example, MV is clipped according to the bounding            block for reference sample padding (e.g., (xSbInt_(L),            ySbInt_(L)) as defined in 8.5.6.3.1) only when DMVR is            applied.            -   i. For example, operations 8-775 and 8-776 in the luma                sample interpolation filtering process as defined in                JVET-O2001-v14 are applied only if DMVR is used for the                current block.            -   ii. For example, operations 8-789 and 8-790 in the                chroma sample interpolation filtering process as defined                in JVET-O2001-v14 are applied only if DMVR is used for                the current block.        -   b. Alternatively, furthermore, the above methods may be also            applicable to the clipping of chroma samples.

    -   8. It is proposed that whether to and/or how to clip MV        according to the bounding block for reference sample padding        (e.g., (xSbInt_(L), ySbInt_(L)) as defined in 8.5.6.3.1 in        JVET-O2001-v14) may depend on whether picture wrapping is used        (e.g. whether sps_ref_wraparound_enabled_flag is equal to 0 or        1).        -   a. In one example, MV is clipped according to the bounding            block for reference sample padding (e.g., (xSbInt_(L),            ySbInt_(L)) as defined in 8.5.6.3.1) only if picture            wrapping is not used.            -   i. For example, operations 8-775 and 8-776 in the luma                sample interpolation filtering process as defined in                JVET-O2001-v14 are applied only if picture wrapping is                not used.            -   ii. For example, operations 8-789 and 8-790 in the                chroma sample interpolation filtering process as defined                in JVET-O2001-v14 are applied only if picture wrapping                is not used.        -   b. Alternatively, furthermore, the above methods may be also            applicable to the clipping of chroma samples.        -   c. In one example, the luma locations in full-sample units            are modified as:

xInt_(i)=Clip3(xSbInt_(L) −Dx,xSbInt_(L)+sbWidth+Ux,xInt_(i)),

yInt_(i)=Clip3(ySbInt_(L) −Dy,ySbInt_(L)+sbHeight+Uy,yInt_(i)),

-   -   -   -   where Dx and/or Dy and/or Ux and/or Uy may depend on                whether picture wrapping is used.

        -   d. In one example, the chroma locations in full-sample units            are modified as:

xInti=Clip3(xSbInt_(C) −Dx,xSbInt_(C)+sbWidth+Ux,xInti)

yInti=Clip3(ySbInt_(C) −Dy,ySbInt_(C)+sbHeight+Uy,yInti)

-   -   -   -   where Dx and/or Dy and/or Ux and/or Uy may depend on                whether picture wrapping is used.

    -   9. Whether to/how to apply filtering process (e.g., deblocking        filter) may depend on whether the reference pictures are with        different resolutions.        -   a. In one example, the boundary strength settings in the            deblocking filters may take the resolution differences into            consideration in addition to motion vector differences.        -   b. In one example, the boundary strength settings in the            deblocking filters may the scaled motion vector differences            based on resolution differences.        -   c. In one example, the strength of deblocking filter is            increased if the resolution of at least one reference            picture of block A is different to (or smaller than or            larger than) the resolution of at least one reference            picture of block B.        -   d. In one example, the strength of deblocking filter is            decreased if the resolution of at least one reference            picture of block A is different to (or smaller than or            larger than) the resolution of at least one reference            picture of block B.        -   e. In one example, the strength of deblocking filter is            increased if the resolution of at least one reference            picture of block A and/or block B is different to (or            smaller than or larger than) the resolution of the current            block.        -   f. In one example, the strength of deblocking filter is            decreased if the resolution of at least one reference            picture of block A and/or block B is different to (or            smaller than or larger than) the resolution of the current            block.

    -   10. Instead of storing/using the motion vectors for a block        based on the same reference picture resolution as current        picture, it is proposed to use the real motion vectors with the        resolution difference taken into consideration.        -   a. Alternatively, furthermore, when using the motion vector            to generate the prediction block, there is no need to            further change the motion v vector according to the            resolutions of the current picture and the reference picture            (e.g. (refx_(L), refy_(L)) derived in 8.5.6.3.1 in            JVET-O2001-v14).

    -   11. In one example, when a sub-picture exists, the reference        picture must have the same resolution as the current picture.        -   a. Alternatively, when a reference picture has a different            resolution to the current picture, there must be no            sub-picture in the current picture.

    -   12. In one example, sub-pictures may be defined separately for        pictures with different resolutions.

    -   13. In one example, the corresponding sub-picture in the        reference picture can be derived by scaling and/or offsetting a        sub-picture of the current picture, if the reference picture has        a different resolution to the current picture.

    -   14. It is proposed that all or partial information associated        with wrap-around clipping may be signaled in a video unit other        than at sequence level, such as at        picture/view/slice/tile/brick/Sub-picture/CTU row level etc. al.        -   a. In one example, the information may be signaled in in            PPS, APS, picture header, slice header, etc.        -   b. For example, a syntax element (e.g., named as            pps_ref_wraparound_offset_minus1) may be signaled in a first            PPS to indicate the offset used for computing the horizontal            wrap-around position.            -   i. In one example, pps_ref_wraparound_offset_minus1 may                be signaled and pps_ref_wraparound_offset_minus1 plus 1                specifies the offset used for computing the horizontal                wrap-around position in units of MinCbSizeY luma samples                wherein MinCbSizeY represents the smallest Cb size of                luma blocks.            -   ii. The range of pps_ref_wraparound_offset_minus1 may                depend on pic_width_in_luma_samples is in the first PPS.                For example, the value of                pps_ref_wraparound_offset_minus1 shall be in the range                of (CtbSizeY/MinCbSizeY)+1 to                (pic_width_in_luma_samples/MinCbSizeY)−1, inclusive,                where pic_width_in_luma_samples is in the first PPS.            -   iii. In one example, the syntax element may be coded                with fixed length/truncated unary/unary/truncated                binary/K-th EG (e.g., K=0) binarization method.        -   c. For example, a syntax element (e.g., named as            pps_ref_wraparound_enabled_flag) may be signaled in a first            PPS to indicate whether horizontal wrap-around motion            compensation is applied in inter prediction.            -   i. In one example, pps_ref_wraparound_enabled_flag equal                to 1 specifies that horizontal wrap-around motion                compensation is applied in inter prediction.                pps_ref_wraparound_enabled_flag equal to 0 specifies                that horizontal wrap-around motion compensation is not                applied.            -   ii. Alternatively, furthermore, the syntax element may                be conditionally signaled.                -   1) In one example, whether to signal                    pps_ref_wraparound_offset_minus1 may depend on                    pps_ref_wraparound_enabled_flag.                -    a) For example, pps_ref_wraparound_offset_minus1 is                    signaled only if pps_ref_wraparound_enabled_flag is                    equal to 1.        -   d. In one example, a first syntax element may be signaled in            a first video unit such as at sequence level (e.g., signaled            in SPS), and a second syntax element may be signaled in a            second video unit such as at picture/slice level (e.g.,            signaled in PPS, APS, picture header, slice header, etc).            The first syntax element and the second syntax element may            have the same functionality on wrap-around clipping but at            different levels.            -   i. The second video unit may refer to the first video                unit.            -   ii. For example, sps_ref_wraparound_offset_minus1 may be                signaled in SPS and pps_ref_wraparound_offset_minus1 may                be signaled in PPS.            -   iii. For example, sps_ref_wraparound_enabled_flag may be                signaled in SPS and pps_ref_wraparound_enabled_flag may                be signaled in PPS.            -   iv. In one example, in a conformance bit-stream, the                first syntax element should be identical to the second                syntax element.                -   1) For example, in a conformance bit-stream,                    sps_ref_wraparound_enabled_flag should be equal to                    pps_ref_wraparound_enabled_flag.            -   v. In one example, the second syntax element may depend                on the first syntax element.                -   1) For example, pps_ref_wraparound_enabled_flag must                    be 0 if sps_ref_wraparound_enabled_flag is 0.                -   2) For example, pps_ref_wraparound_enabled_flag can                    0 or 1 if sps_ref_wraparound_enabled_flag is 1.            -   vi. In one example, the first syntax element is ignored,                and the second syntax element takes the functionality if                the two syntax elements both appear.            -   vii. In one example, the second syntax element is                ignored, and the first syntax element takes the                functionality if the two syntax elements both appear.        -   e. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is not less than or equal to            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is the value of            pic_width_in_luma_samples in any PPS that refers to the SPS,            the value of sps_ref_wraparound_enabled_flag shall be equal            to 0. E.g. Offset1=Offset2=1.        -   f. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is not less than            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is the value of            pic_width_in_luma_samples in any PPS that refers to the SPS,            the value of sps_ref_wraparound_enabled_flag shall be equal            to 0. E.g. Offset1=Offset2=1.        -   g. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is greater than or equal to            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is the value of            pic_width_in_luma_samples in any PPS that refers to the SPS,            the value of sps_ref_wraparound_enabled_flag shall be equal            to 0. E.g. Offset1=Offset2=1.        -   h. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is greater than            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is the value of            pic_width_in_luma_samples in any PPS that refers to the SPS,            the value of sps_ref_wraparound_enabled_flag shall be equal            to 0. E.g. Offset1=Offset2=1.        -   i. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is not less than or equal to            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is in PPS the value of            pps_ref_wraparound_enabled_flag shall be equal to 0. E.g.            Offset1=Offset2=1.        -   j. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is not less than            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is in PPS the value of            pps_ref_wraparound_enabled_flag shall be equal to 0. E.g.            Offset1=Offset2=1.        -   k. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is greater than or equal to            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is in PPS the value of            pps_ref_wraparound_enabled_flag shall be equal to 0. E.g.            Offset1=Offset2=1.        -   l. In one example, when the value of            (CtbSizeY/MinCbSizeY+Offset1) is greater than            (pic_width_in_luma_samples/MinCbSizeY_Offset2), where            pic_width_in_luma_samples is in PPS the value of            pps_ref_wraparound_enabled_flag shall be equal to 0. E.g.            Offset1=Offset2=1.

    -   15. It is proposed that an equation of Log 2(X) with X equal to        or less than 0 should be avoided to derive the affine merge        candidates.        -   a. For example, the procedure may be conditioned on whether            X is larger than 0 or not.        -   b. For example, the procedure may be conditioned on whether            X is equal to 0 or not.        -   c. For example, Log 2(Height)−Log 2(Width) are calculated            instead of Log 2(Height/Width)        -   d. An exemplary spec change based on JVET-P2001-v9 is as            below:            8.5.5.6 Derivation process for constructed affine control            point motion vector merging candidates            . . .            6. When availableFlagCorner[0] is equal to TRUE and            availableFlagCorner[2] is equal to TRUE, the following            applies:

    -   For X being replaced by 0 or 1, the following applies:        -   The variable availableFlagLX is derived as follows:            -   If all of following conditions are TRUE, availableFlagLX                is set equal to TRUE:                -   predFlagLXCorner[0] is equal to 1                -   predFlagLXCorner[2] is equal to 1                -   refIdxLXCorner[0] is equal to refIdxLXCorner[2]            -   Otherwise, availableFlagLX is set equal to FALSE.        -   When availableFlagLX is equal to TRUE, the following            applies:            -   The second control point motion vector cpMvLXCorner[1]                is derived as follows:

cpMvLXCorner[1][0]=(cpMvLXCorner[0][0]<<7)+((cpMvLXCorner[2][1]−cpMvLXCorner[0][1])<<(7+Log2(cbHeight)−Log 2(cbWidth)[[Log 2(cbHeight/cbWidth)]]))  (8-625)

cpMvLXCorner[1][1]=(cpMvLXCorner[0][1]<<7)+((cpMvLXCorner[2][0]cpMvLXCorner[0][0])<<(7+Log2(cbHeight)−Log 2(cbWidth)[[Log 2(cbHeight/cbWidth)]]))  (8-626)

-   -   -   -   The rounding process for motion vectors as specified in                clause 8.5.2.14 is invoked with mvX set equal to                cpMvLXCorner[1], rightShift set equal to 7, and                leftShift set equal to 0 as inputs and the rounded                cpMvLXCorner[1] as output.            -   The following assignments are made:

predFlagLXConst6=1  (8-627)

refIdxLXConst6=refIdxLXCorner[0]  (8-628)

cpMvLXConst6[0]=cpMvLXCorner[0]  (8-629)

cpMvLXConst6[1]=cpMvLXCorner[1]  (8-630)

cpMvLXConst6[0][0]=Clip3(−2¹⁷,2¹⁷−1,cpMvLXConst6[0][0])  (8-631)

cpMvLXConst6[0][1]=Clip3(−2¹⁷,2¹⁷−1,cpMvLXConst6[0][1])  (8-632)

cpMvLXConst6[1][0]=Clip3(−2¹⁷,2¹⁷−1,cpMvLXConst6[1][0])  (8-633)

cpMvLXConst6[1][1]=Clip3(−2¹⁷,2¹⁷−1,cpMvLXConst6[1][1])  (8-634)

-   -   The bi-prediction weight index bcwIdxConst6 is set equal to        bcwIdxCorner[0].    -   The variables availableFlagConst6 and motionModelIdcConst6 are        derived as follows:        -   If availableFlagL0 or availableFlagL1 is equal to 1,            availableFlagConst6 is set equal to TRUE and            motionModelIdcConst6 is set equal to 1.            Otherwise, availableFlagConst6 is set equal to FALSE and            motionModelIdcConst6 is set equal to 0.    -   16. It is proposed that an equation of Log 2(X) with X equal to        or less than 0 should be avoided in the procedure to derive the        parameters in Cross-Component Linear Model (CCLM).        -   a. For example, the procedure may be conditioned on whether            X is larger than 0 or not.        -   b. For example, the procedure may be conditioned on whether            X is equal to 0 or not.        -   c. An exemplary spec change based on JVET-P2001-v9 is as            below:            8.4.5.2.13 Specification of INTRA_LT_CCLM, INTRA_L_CCLM and            INTRA_T_CCLM intra prediction mode    -   . . .    -   7. The variables a, b, and k are derived as follows:        -   If numSampL is equal to 0, and numSampT is equal to 0, the            following applies:

k=0  (8-211)

a=0  (8-212)

b=1<<(BitDepth−1)  (8-213)

-   -   -   Otherwise, the following applies:

diff=maxY−minY  (8-214)

-   -   -   -   If diff is not equal to 0, the following applies:

diffC=maxC−minC  (8-215)

x=Floor(Log 2(diff))  (8-216)

normDiff=((diff<<4)>>x)&15  (8-217)

x+=(normDiff!=0)?1:0  (8-218)

y=diffC>0?Floor(Log 2(Abs(diffC)))+1:0  (8-219)

a=(diffC*(divSigTable[normDiff]|8)+2^(y−1))>>y  (8-220)

k=((3+x−y)<1)?1:3+x−y  (8-221)

a=((3+x−y)<1)?Sign(a)*15:a  (8-222)

b=minC−((a*minY)>>k)  (8-223)

-   -   -   -   -   where divSigTable[ ] is specified as follows:

divSigTable[ ]={0,7,6,5,5,4,4,3,3,2,2,1,1,1,1,0}  (8-224)

-   -   -   -   Otherwise (diff is equal to 0), the following applies:

k=0  (8-225)

a=0  (8-226)

b=minC  (8-227)

-   -   -   . . .        -   d. More exemplary spec changes based on JVET-P2001-v9 is as            below

i. y=Abs(diffC)>0?Floor(Log 2(Abs(diffC)))+1:0:

ii. y=diffC==0?0: Floor(Log 2(Abs(diffC)))+1:

iii. y=Ceil(Log 2(Abs(diffC)+1)))

-   -   17. It is proposed that dividing by 0 should be avoided in the        procedure of angular intra-prediction        -   e. For example, the derivation of invAngle may be            conditioned on whether intraPredAngle is equal to 0 or not.        -   f. An exemplary spec change based on JVET-P2001-v9 is as            below:            8.4.5.2.12 Specification of INTRA_ANGULAR2 . . .            INTRA_ANGULAR66 intra prediction modes            Inputs to this process are:    -   the intra prediction mode predModeIntra,    -   a variable refIdx specifying the intra prediction reference line        index,    -   a variable nTbW specifying the transform block width,    -   a variable nTbH specifying the transform block height,    -   a variable refW specifying the reference samples width,    -   a variable refH specifying the reference samples height,    -   a variable nCbW specifying the coding block width,    -   a variable nCbH specifying the coding block height,    -   a variable refFilterFlag specifying the value of reference        filter flag,    -   a variable cIdx specifying the colour component of the current        block,    -   the neighbouring samples p[x][y], with x=−1−refIdx, y=−1−refIdx        . . . refH−1 and x=−refIdx . . . refW−1, y=−1−refIdx.        Outputs of this process are the predicted samples        predSamples[x][y], with x=0 . . . nTbW−1, y=0 . . . nTbH−1.        The variable nTbS is set equal to (Log 2 (nTbW)+Log 2        (nTbH))>>1.        The variable filterFlag is derived as follows:    -   If one or more of the following conditions is true, filterFlag        is set equal to 0.        -   refFilterFlag is equal to 1        -   refIdx is not equal to 0        -   IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT    -   Otherwise, the following applies:        -   The variable minDistVerHor is set equal to            Min(Abs(predModeIntra−50), Abs(predModeIntra−18)).        -   The variable intraHorVerDistThres[nTbS] is specified in            Table 8-7.        -   The variable filterFlag is derived as follows:            -   If minDistVerHor is greater than                intraHorVerDistThres[nTbS] and refFilterFlag is equal to                0, filterFlag is set equal to 1.            -   Otherwise, filterFlag is set equal to 0.

TABLE 8-7 Specification of intraHorVerDistThres[ nTbS ] for varioustransform block sizes nTbS nTbS = 2 nTbS = 3 nTbS = 4 nTbS = 5 nTbS = 6nTbS = 7 intraHorVerDistThres[ nTbS ] 24 14 2 0 0 0Table 8-8 specifies the mapping table between predModeIntra and theangle parameter intraPredAngle.

TABLE 8-8 Specification of intraPredAngle predModeIntra −14 −13 −12 −11−10 −9 −8 −7 −6 −5 −4 −3 −2 −1 2 3 4 intraPredAngle 512 341 256 171 128102 86 73 64 57 51 45 39 35 32 29 26 predModeIntra 5 6 7 8 9 10 11 12 1314 15 16 17 18 19 20 21 intraPredAngle 23 20 18 16 14 12 10 8 6 4 3 2 10 −1 −2 −3 predModeIntra 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 3738 intraPredAngle −4 −6 −8 −10 −12 −14 −16 −18 −20 −23 −26 −29 −32 −29−26 −23 −20 predModeIntra 39 40 41 42 43 44 45 46 47 48 49 50 51 52 5354 55 intraPredAngle −18 −16 −14 −12 −10 −8 −6 −4 −3 −2 −1 0 1 2 3 4 6predModeIntra 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72intraPredAngle 8 10 12 14 16 18 20 23 26 29 32 35 39 45 51 57 64predModeIntra 73 74 75 76 77 78 79 80 intraPredAngle 73 86 102 128 171256 341 512The inverse angle parameter invAngle is derived based on intraPredAngleas follows:

$\begin{matrix}{{invAngle} = {{intraPredAngle}=={{0?\text{0:}}\mspace{14mu}{{Round}( \frac{512*32}{intraPredAngle} )}}}} & \text{(8-129)}\end{matrix}$

-   -   18. Whether and/or how to apply the integer sample clipping        operation on luma and/or chroma samples may depend on the width        and/or height of the reference picture (or its conformance        window, or its scaling window), and the width and/or height of        the current picture (or its conformance window, or its scaling        window).        -   a. In one example, the integer sample clipping operation is            applied only if the width and/or height of the reference            picture (or its conformance window, or its scaling window)            is equal to width and/or height of the current picture (or            its conformance window, or its scaling window).            -   i. Alternatively, furthermore, if either width or height                of the reference picture (or its conformance window, or                its scaling window) is unequal to that of the current                picture (or its conformance window, or its scaling                window), the integer sample clipping operation is                skipped.        -   b. Alternatively, whether and/or how to apply the integer            sample clipping operation on luma and/or chroma samples may            depend on the horizontal and/or vertical scaling factor            between the reference picture (or its conformance window, or            its scaling window) and that of the current picture (or its            conformance window, or its scaling window).            -   i. In one example, the integer sample clipping operation                is applied only if the horizontal and/or vertical                scaling factor between the reference picture (or its                conformance window, or its scaling window) and that of                the current picture (or its conformance window, or its                scaling window) is equal to 1.            -   ii. Alternatively, if the horizontal or vertical scaling                factor is unequal to 1, the integer sample clipping                operation is skipped.        -   c. In one example, the integer sample clipping operation on            horizontal direction is conditioned by the width of the            reference picture (or its conformance window, or its scaling            window) and the width of the current picture (or its            conformance window, or its scaling window).            -   i. In one example, the integer sample clipping operation                on horizontal direction is conditioned by the horizontal                scaling factor between the reference picture (or its                conformance window, or its scaling window) and that of                the current picture (or its conformance window, or its                scaling window).        -   d. In one example, the integer sample clipping operation on            vertical direction is conditioned by the height of the            reference picture (or its conformance window, or its scaling            window) and the height of the current picture (or its            conformance window, or its scaling window).            -   i. In one example, the integer sample clipping operation                on vertical direction is conditioned by the vertical                scaling factor between the reference picture (or its                conformance window, or its scaling window) and that of                the current picture (or its conformance window, or its                scaling window).        -   e. An exemplary spec change based on JVET-P2001-v9 is as            below:

8.5.6.3.2 Luma Sample Interpolation Filtering Process

. . .

The luma locations in full-sample units (xInt_(i), yInt_(i)) are derivedas follows for i=0 . . . 7:

-   -   If subpic_treated_as_pic_flag[SubPicIdx] is equal to 1, the        following applies:

xInt_(i)=Clip3(SubPicLeftBoundaryPos,SubPicRightBoundaryPos,xInt_(L)+i−3)  (8-754)

yInt_(i)=Clip3(SubPicTopBoundaryPos,SubPicBotBoundaryPos,yInt_(L)+i−3)  (8-755)

-   -   Otherwise (subpic_treated_as_pic_flag[SubPicIdx] is equal to 0),        the following applies:

xInt_(i)=Clip3(0,picW−1,sps_ref_wraparound_enabled_flag?ClipH((sps_ref_wraparound_offset_minus1+1)*MinCbSizeY,picW,xInt_(L)+i−3):xInt_(i) +i−3)

yInt_(i)=Clip3(0,picH−1,yInt_(L) +i−3)

If hori_scale_fp is equal to (1<<14) and vert_scale_fp is equal to(1<<14), the luma locations in full-sample units are further modified asfollows for i=0 . . . 7:

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))

yInt_(i)=Clip3(ySbInt_(L)−3,ySbInt_(L)+sbHeight+4,yInt_(i))

The predicted luma sample value predSampleLX_(L) is derived as follows:

-   -   If both xFrac_(L) and yFrac_(L) are equal to 0, and both        hori_scale_fp and vert_scale_fp are less than 20481, the value        of predSampleLX_(L) is derived as follows:

predSampleLX _(L)=refPicLX _(L)[xInt₃][yInt₃]<<shift3

. . .

8.5.6.3.4 Chroma Sample Interpolation Process

. . .

If hori_scale_fp is equal to (1<<14) and vert_scale_fp is equal to(1<<14), the chroma locations in full-sample units (xInt_(i), yInt_(i))are further modified as follows for i=0 . . . 3:

xInt_(i)=Clip3(xSbIntC−1,xSbIntC+sbWidth+2,xInt_(i))  (8-774)

yInt_(i)=Clip3(ySbIntC−1,ySbIntC+sbHeight+2,yInt_(i))  (8-775)

. . .

-   -   f. Another exemplary spec change based on JVET-P2001-v9 is as        below:

8.5.6.3.2 Luma Sample Interpolation Filtering Process

. . .

The luma locations in full-sample units (xInt_(i), yInt_(i)) are derivedas follows for i=0 . . . 7:

-   -   If subpic_treated_as_pic_flag[SubPicIdx] is equal to 1, the        following applies:

xInt_(i)=Clip3(SubPicLeftBoundaryPos,SubPicRightBoundaryPos,xInt_(L)+i−3)  (8-754)

yInt_(i)=Clip3(SubPicTopBoundaryPos,SubPicBotBoundaryPos,yInt_(L)+i−3)  (8-755)

-   -   Otherwise (subpic_treated_as_pic_flag[SubPicIdx] is equal to 0),        the following applies:

xInt_(i)=Clip3(0,picW−1,sps_ref_wraparound_enabled_flag?ClipH((sps_ref_wraparound_offset_minus'+1)*MinCbSizeY,picW,xInt_(L)+i−3):xInt_(L) +i−3)

yInt_(i)=Clip3(0,picH−1,yInt_(L) +i−3)

The luma locations in full-sample units are further modified as followsfor i=0 . . . 7:

If hori_scale_fp is equal to (1<<14) and vert_scale_fp is equal to(1<<14),

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))

If hori_scale_fp is equal to (1<<14) and vert_scale_fp is equal to(1<<14),

yInt_(i)=Clip3(ySbInt_(L)−3,ySbInt_(L)+sbHeight+4,yInt_(i))

The predicted luma sample value predSampleLX_(L) is derived as follows:

-   -   If both xFrac_(L) and yFrac_(L) are equal to 0, and both        hori_scale_fp and vert_scale_fp are less than 20481, the value        of predSampleLX_(L) is derived as follows:

predSampleLX _(L)=refPicLX _(L)[xInt₃][yInt₃]<<shift3

. . .

8.5.6.3.4 Chroma Sample Interpolation Process

. . .

The chroma locations in full-sample units (xInt_(i), yInt_(i)) arefurther modified as follows for i=0 . . . 3:

If hori_scale_fp is equal to (1<<14) and vert_scale_fp is equal to(1<<14),

xInt_(i)=Clip3(xSbIntC−1,xSbIntC+sbWidth+2,xInt_(i))  (8-774)

If hori_scale_fp is equal to (1<<14) and vert_scale_fp is equal to(1<<14),

yInt_(i)=Clip3(ySbIntC−1,ySbIntC+sbHeight+2,yInt_(i))  (8-775)

. . .

-   -   g. In one example, whether to apply the integer sample clipping        operation may depend on the width and/or height of the reference        pictures of the two reference lists (or their conformance        windows, or their scaling windows), and the width and/or height        of the current picture (or its conformance window, or its        scaling window).        -   i. In one example, the integer sample clipping operation is            applied only if the width and/or height of all the reference            pictures (e.g. from reference list 0, or from reference list            1, or from both) used by the current block (or their            conformance windows, or their scaling windows) are equal to            width and/or height of the current picture (or its            conformance window, or its scaling window).            -   1) Alternatively, furthermore, if either width or height                of any reference picture (e.g. from reference list 0, or                from reference list 1) used by the current block (or its                conformance window, or its scaling window) is unequal to                that of the current picture (or its conformance window,                or its scaling window), the integer sample clipping                operation is skipped.    -   h. An exemplary spec change based on JVET-P2001-v14 is as below:

8.5.6.3.2 Luma Sample Interpolation Filtering Process

Inputs to this process are:

-   -   a luma location in full-sample units (xInt_(L), yInt_(L)),        -   . . .

When RefPicIsScaled[0][refIdxL0] is equal to 0 andRefPicIsScaled[1][refIdxL1] is equal to 0, the luma locations infull-sample units are further modified as follows for i=0 . . . 7:

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))  (959)

yInt_(i)=Clip3(ySbInt_(L)−3,y SbInt_(L)+sbHeight+4,yInt_(i))  (960)

The predicted luma sample value predSampleLX_(L) is derived as follows:

8.5.6.3.4 Chroma Sample Interpolation Process

Inputs to this process are:

-   -   a chroma location in full-sample units (xInt_(C), yInt_(C)),        . . .        When RefPicIsScaled[0][refIdxL0] is equal to 0 and        RefPicIsScaled[1][refIdxL1] is equal to 0, the chroma locations        in full-sample units (xInt_(i), yInt_(i)) are further modified        as follows for i=0 . . . 3:

xInt_(i)=Clip3(xSbIntC−1,xSbIntC+sbWidth+2,xInt_(i))  (975)

yInt_(i)=Clip3(ySbIntC−1,ySbIntC+sbHeight+2,yInt_(i))  (976)

The predicted chroma sample value predSampleLXc is derived as follows:. . .

-   -   i. In one example, whether to apply the integer sample clipping        operation may depend on whether DMVR is applied.    -   j. An exemplary spec change based on JVET-P2001-v14 is as below:

8.5.6.3.2 Luma sample interpolation filtering process

Inputs to this process are:

-   -   a luma location in full-sample units (xInt_(L), yInt_(L)),        -   . . .            When dmvrFlag is equal to 1, the luma locations in            full-sample units are further modified as follows for i=0 .            . . 7:

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))  (959)

yInt_(i)=Clip3(ySbInt_(L)−3,ySbInt_(L)+sbHeight+4,yInt_(i))  (960)

The predicted luma sample value predSampleLX_(L) is derived as follows:

-   -   . . .

8.5.6.3.4 Chroma Sample Interpolation Process

Inputs to this process are:

-   -   a chroma location in full-sample units (xInt_(C), yInt_(C)),        . . .        When dmvrFlag is equal to 1, the chroma locations in full-sample        units (xInt_(i), yInt_(i)) are further modified as follows for        i=0 . . . 3:

xInt_(i)=Clip3(xSbIntC−1,xSbIntC+sbWidth+2,xInt_(i))  (975)

yInt_(i)=Clip3(ySbIntC−1,ySbIntC+sbHeight+2,yInt_(i))  (976)

The predicted chroma sample value predSampleLXc is derived as follows:. . .

-   -   19. Whether and/or how to apply the integer sample clipping        operation on luma and/or chroma samples may depend on whether a        coding tool X is applied. (E.g. X is Decoder-side Motion Vector        Refinement (DMVR)).        -   a. In one example, the integer sample clipping operation is            applied only if coding tool X is applied.        -   b. In one example, the integer sample clipping operation is            applied only if coding tool X is not applied.

GEO Related

-   -   20. Which angles/distances are allowed to be used in GEO may be        dependent on the decoded information (e.g., related syntax        elements, block dimensions).        -   a. In one example, which angles/distances can be used in GEO            may be dependent on the block dimensions.            -   i. In one example, a set of angles/distances may be used                for block dimensions A (e.g., A may indicate blocks with                Height larger than Width), while another set of                angles/distances may be used for block dimensions B                (e.g., B may indicate blocks with Height NOT larger than                Width).        -   b. In one example, how to map the GEO mode indices to            angle/distance indices may be dependent on the decoded            information (e.g., related syntax elements, block            dimensions).        -   c. In one example, how to map the decoded/signalled GEO mode            indices to the GEO mode indices used for deriving GEO            angle/distance indices may be dependent on the decoded            information (e.g., related syntax elements, block            dimensions).        -   d. In one example, how to map the decoded/signalled GEO mode            indices to GEO angle/distance indices may be dependent on            the decoded information (e.g., related syntax elements,            block dimensions).        -   e. An exemplary spec change based on            JVET-Q0160_CE4_1_CommonBaseWD_w_fixes is as below, where the            newly added texts are shown in underlined bold font. The            deleted texts are marked by inclusion in [[ ]] square            brackets.

8.5.7 Decoding Process for Geo Inter Blocks 8.5.7.1 General

This process is invoked when decoding a coding un withMergeGeoFlag[xCb][yCb] equal to 1.Inputs to this process are:

-   -   a luma location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left luma sample of the        current picture,    -   a variable cbWidth specifying the width of the current coding        block in luma samples,    -   a variable cbHeight specifying the height of the current coding        block in luma samples,    -   the luma motion vectors in 1/16 fractional-sample accuracy mvA        and mvB,    -   the chroma motion vectors mvCA and mvCB,    -   the reference indices refIdxA and refIdxB,    -   the prediction list flags predListFlagA and predListFlagB.        Outputs of this process are:    -   an (cbWidth)×(cbHeight) array predSamples_(L) of luma prediction        samples,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC) array        predSamples_(Cr) of chroma prediction samples for the component        Cb,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC) array        predSamples_(Cr) of chroma prediction samples for the component        Cr.        Let predSamplesLA_(L) and predSamplesLB_(L) be        (cbWidth)×(cbHeight) arrays of predicted luma sample values and,        predSamplesLA_(Cb), predSamplesLB_(Cb), predSamplesLA_(Cr) and        predSamplesLB_(Cr) be (cbWidth/SubWidthC)×(cbHeight/SubHeightC)        arrays of predicted chroma sample values.        The predSamples_(L), predSamples_(Cb) and predSamples_(Cr) are        derived by the following ordered steps:    -   1. For N being each of A and B, the following applies:        -   The reference picture consisting of an ordered            two-dimensional array refPicLN_(L) of luma samples and two            ordered two-dimensional arrays refPicLN_(Cb) and            refPicLN_(Cr) of chroma samples is derived by invoking the            process specified in clause 8.5.6.2 with X set equal to            predListFlagN and refIdxX set equal to refIdxN as input.        -   The array predSamplesLN_(L) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the luma coding            block width sbWidth set equal to cbWidth, the luma coding            block height sbHeight set equal to cbHeight, the motion            vector offset mvOffset set equal to (0, 0), the motion            vector mvLX set equal to mvN and the reference array            refPicLX_(L) set equal to refPicLN_(L), the variable            bdofFlag set equal to FALSE, the variable cIdx is set equal            to 0, and RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cb) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cb) set equal to refPicLN_(Cb), the variable            bdofFlag set equal to FALSE, the variable cIdx is set equal            to 1, and RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cr) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cr) set equal to refPicLN_(Cr), the variable            bdofFlag set equal to FALSE, the variable cIdx is set equal            to 2, and RefPicScale[predListFlagN][refIdxN] as inputs.    -   2. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to Table 36, with the        value of merge_geo_partition_idx[xCb][yCb], and the variable        isNarrowBlk set equal to cbHeight>cbWidth as inputs.    -   3. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to [[the value of        merge_geo_partition_idx[xCb][yCb] as specified in]] Table 36,        with the value of merge_geo_partition_idx[xCb][yCb], and the        variable isNarrowBlk set equal to cbHeight>cbWidth as inputs.    -   4. The prediction samples inside the current luma coding block,        predSamples_(L)[x_(L)][y_(L)] with x_(L)=0 . . . cbWidth−1 and        y_(L)=0 . . . cbHeight−1, are derived by invoking the weighted        sample prediction process for geo merge mode specified in clause        8.5.7.2 with the coding block width nCbW set equal to cbWidth,        the coding block height nCbH set equal to cbHeight, the sample        arrays predSamplesLA_(L) and predSamplesLB_(L), and the        variables angleIdx and distanceIdx, and cIdx equal to 0 as        inputs.    -   5. The prediction samples inside the current chroma component Cb        coding block, predSamples_(Cb)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cb) and predSamplesLB_(Cb), and the variables        angleIdx and distanceIdx, and cIdx equal to 1 as inputs.    -   6. The prediction samples inside the current chroma component Cr        coding block, predSamples_(Cr)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cr) and predSamplesLB_(Cr), and the variables        angleIdx and distanceIdx, and cIdx equal to 2 as inputs.    -   7. The motion vector storing process for merge geo mode        specified in clause 8.5.7.3 is invoked with the luma coding        block location (xCb, yCb), the luma coding block width cbWidth,        the luma coding block height cbHeight, the partition direction        angleIdx and distanceIdx, the luma motion vectors mvA and mvB,        the reference indices refIdxA and refIdxB, and the prediction        list flagspredListFlagA and predListFlagB as inputs.        Table 36—Specification of the angleIdx and distanceIdx Values        Based on the Merge_Geo_Partition_Idxvalue.

FIGS. 9A and 9B show an example embodiment of Table 36.

-   -   i. Another exemplary spec change based on        JVET-Q0160_CE4_1_CommonBaseWD_w_fixes is as below:

8.5.6 Decoding Process for Geo Inter Blocks 8.5.7.1 General

This process is invoked when decoding a coding unit withMergeGeoFlag[xCb][yCb] equal to 1.Inputs to this process are:

-   -   a luma location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left luma sample of the        current picture,    -   a variable cbWidth specifying the width of the current coding        block in luma samples,    -   a variable cbHeight specifying the height of the current coding        block in luma samples,    -   the luma motion vectors in 1/16 fractional-sample accuracy mvA        and mvB,    -   the chroma motion vectors mvCA and mvCB,    -   the reference indices refIdxA and refIdxB,    -   the prediction list flags predListFlagA and predListFlagB.        Outputs of this process are:    -   an (cbWidth)×(cbHeight) arraypredSamples_(L) of luma prediction        samples,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC) array        predSamples_(Cb) of chroma prediction samples for the component        Cb,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC)        arraypredSamples_(Cr) of chroma prediction samples for the        component Cr.        Let predSamplesLA_(L) and predSamplesLB_(L) be        (cbWidth)×(cbHeight) arrays of predicted luma sample values and,        predSamplesLA_(Cb), predSamplesLB_(Cb), predSamplesLA_(Cr) and        predSamplesLB_(Cr) be (cbWidth/SubWidthC)×(cbHeight/SubHeightC)        arrays of predicted chroma sample values.        The predSamples_(L), predSamples_(Cb) and predSamples_(Cr) are        derived by the following ordered steps:    -   1. For N being each of A and B, the following applies:        -   The reference picture consisting of an ordered            two-dimensional array refPicLN_(L) of luma samples and two            ordered two-dimensional arrays refPicLN_(Cb) and            refPicLN_(Cr) of chroma samples is derived by invoking the            process specified in clause 8.5.6.2 with X set equal to            predListFlagN and refIdxX set equal to refIdxN as input.        -   The array predSamplesLN_(L) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the luma coding            block width sbWidth set equal to cbWidth, the luma coding            block height sbHeight set equal to cbHeight, the motion            vector offset mvOffset set equal to (0, 0), the motion            vector mvLX set equal to mvN and the reference array            refPicLX_(L) set equal to refPicLN_(L) the variable bdofFlag            set equal to FALSE, the variable cIdx is set equal to 0, and            RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cb) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cb) set equal to refPicLN_(Cb), the variable            bdofFlagset equal to FALSE, the variable cIdx is set equal            to 1, and RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cr) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cr) set equal to refPicLN_(Cr), the variable            bdofFlag set equal to FALSE, the variable cIdx is set equal            to 2, and RefPicScale[predListFlagN][refIdxN] as inputs.    -   2. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to Table 36, with the        value of merge_geo_partition_idx[xCb][yCb], and the variable        isNarrowBlk set equal to cbHeight>cbWidth as inputs.    -   3. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to [[the value of        merge_geo_partition_idx[xCb][yCb] as specified in]] Table 36,        with the value of merge_geo_partition_idx[xCb][yCb], and the        variable isNarrowBlk set equal to cbHeight>cbWidth as inputs.    -   4. The prediction samples inside the current luma coding block,        predSamples_(L)[x_(L)][y_(L)] with x_(L)=0 . . . cbWidth−1 and        y_(L)=0 . . . cbHeight−1, are derived by invoking the weighted        sample prediction process for geo merge mode specified in clause        8.5.7.2 with the coding block widthnCbW set equal to cbWidth,        the coding block heightnCbH set equal to cbHeight, the sample        arrays predSamplesLA_(L) and predSamplesLB_(L), and the        variables angleIdx and distanceIdx, and cIdx equal to 0 as        inputs.    -   5. The prediction samples inside the current chroma component Cb        coding block, predSamples_(Cb)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cb) and predSamplesLB_(Cb), and the variables        angleIdx and distanceIdx, and cIdx equal to 1 as inputs.    -   6. The prediction samples inside the current chroma component Cr        coding block, predSamples_(Cr)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cr) and predSamplesLB_(Cr), and the variables        angleIdx and distanceIdx, and cIdx equal to 2 as inputs.    -   7. The motion vector storing process for merge geo mode        specified in clause 8.5.7.3 is invoked with the luma coding        block location (xCb, yCb), the luma coding block width cbWidth,        the luma coding block height cbHeight, the partition direction        angleIdx and distanceIdx, the luma motion vectors mvA and mvB,        the reference indices refIdxA and refIdxB, and the prediction        list flags predListFlagA and predListFlagB as inputs.        Table 36—Specification of the angleIdx and distanceIdx Values        Based on the Merge_Geo_Partition_Idxvalue.

FIGS. 9C and 9D show an example of this embodiment of Table 36.

-   -   f. Another exemplary spec change based on        JVET-Q0160_CE4_1_CommonBaseWD_w_fixes is as below:

8.5.7 Decoding Process for Geo Inter Blocks 8.5.7.1 General

This process is invoked when decoding a coding unit withMergeGeoFlag[xCb][yCb] equal to 1.Inputs to this process are:

-   -   a luma location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left luma sample of the        current picture,    -   a variable cbWidth specifying the width of the current coding        block in luma samples,    -   a variable cbHeight specifying the height of the current coding        block in luma samples,    -   the luma motion vectors in 1/16 fractional-sample accuracy mvA        and mvB,    -   the chroma motion vectors mvCA and mvCB,    -   the reference indices refIdxA and refIdxB,    -   the prediction list flags predListFlagA and predListFlagB.        Outputs of this process are:    -   an (cbWidth)×(cbHeight) array predSamples_(L) of luma prediction        samples,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC) array        predSamples_(Cb) of chroma prediction samples for the component        Cb,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC)        arraypredSamples_(Cr) of chroma prediction samples for the        component Cr.        Let predSamplesLA_(L) and predSamplesLB_(L) be        (cbWidth)×(cbHeight) arrays of predicted luma sample values and,        predSamplesLA_(Cb), predSamplesLB_(Cb), predSamplesLA_(Cr) and        predSamplesLB_(Cr) be (cbWidth/SubWidthC)×(cbHeight/SubHeightC)        arrays of predicted chroma sample values.        The predSamples_(L), predSamples_(Cb) and predSamples_(Cr) are        derived by the following ordered steps:    -   1. For N being each of A and B, the following applies:        -   The reference picture consisting of an ordered            two-dimensional array refPicLN_(L) of luma samples and two            ordered two-dimensional arrays refPicLN_(Cb) and            refPicLN_(Cr) of chroma samples is derived by invoking the            process specified in clause 8.5.6.2 with X set equal to            predListFlagN and refIdxX set equal to refIdxN as input.        -   The array predSamplesLN_(L) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the luma coding            block width sbWidth set equal to cbWidth, the luma coding            block height sbHeight set equal to cbHeight, the motion            vector offset mvOffset set equal to (0, 0), the motion            vector mvLX set equal to mvN and the reference array            refPicLX_(L) set equal to refPicLN_(L) the variable bdofFlag            set equal to FALSE, the variable cIdx is set equal to 0, and            RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cb) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cb) set equal to refPicLN_(Cb), the variable            bdofFlagset equal to FALSE, the variable cIdx is set equal            to 1, and RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cr) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cr) set equal to refPicLN_(Cr), the variable            bdofFlag set equal to FALSE, the variable cIdx is set equal            to 2, and RefPicScale[predListFlagN][refIdxN] as inputs.    -   2. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to Table 36, with the        value of merge_geo_partition_idx[xCb][yCb], and the variable        isNarrowBlk set equal to cbHeight>cbWidth as inputs.    -   3. The value of merge_geo_parition_idx′[xCb][yCb] are set        according to the value of merge_geo_parition_idx[xCb][yCb] and        the coding block width cbWidth and the coding block height        cbHeight, as specified in Table xx.    -   4. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to the value of        merge_geo_partition_idx[xCb][yCb] as specified in Table 36.    -   5. The prediction samples inside the current luma co ding block,        predSamples_(L)[x_(L)][y_(L)] with x_(L)=0 . . . cbWidth−1 and        y_(L)=0 . . . cbHeight−1, are derived by invoking the weighted        sample prediction process for geo merge mode specified in clause        8.5.7.2 with the coding block width nCbW set equal to cbWidth,        the coding block heightnCbH set equal to cbHeight, the sample        arrays predSamplesLA_(L) and predSamplesLB_(L), and the        variables angleIdx and distanceIdx, and cIdx equal to 0 as        inputs.    -   6. The prediction samples inside the current chroma component Cb        coding block, predSamples_(Cb)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cb) and predSamplesLB_(Cb), and the variables        angleIdx and distanceIdx, and cIdx equal to 1 as inputs.    -   7. The prediction samples inside the current chroma component Cr        coding block, predSamples_(Cr)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cr) and predSamplesLB_(Cr), and the variables        angleIdx and distanceIdx, and cIdx equal to 2 as inputs.    -   8. The motion vector storing process for merge geo mode        specified in clause 8.5.7.3 is invoked with the luma coding        block location (xCb, yCb), the luma coding block width cbWidth,        the luma coding block height cbHeight, the partition direction        angleIdx and distanceIdx, the luma motion vectors mvA and mvB,        the reference indices refIdxA and refIdxB, and the prediction        list flags predListFlagA and predListFlagB as inputs.

FIG. 9E shows this embodiment of Table xx—Mapping table of thegeo_partition_idx′ values based on the geo_partition_idx value

FIG. 9F shows this embodiment of Table 36 Specification of the angleIdxand distanceIdx values based on the merge_geo_partition_idx value.

-   -   g. Another exemplary spec change based on        JVET-Q0160_CE4_1_CommonBaseWD_w_fixes is as below:

8.5.7 Decoding Process for Geo Inter Blocks 8.5.7.1 General

This process is invoked when decoding a coding unit withMergeGeoFlag[xCb][yCb] equal to 1.Inputs to this process are:

-   -   a luma location (xCb, yCb) specifying the top-left sample of the        current coding block relative to the top-left luma sample of the        current picture,    -   a variable cbWidth specifying the width of the current coding        block in luma samples,    -   a variable cbHeight specifying the height of the current coding        block in luma samples,    -   the luma motion vectors in 1/16 fractional-sample accuracy mvA        and mvB,    -   the chroma motion vectors mvCA and mvCB,    -   the reference indices refIdxA and refIdxB,    -   the prediction list flags predListFlagA and predListFlagB.        Outputs of this process are:    -   an (cbWidth)×(cbHeight) arraypredSamples_(L) of luma prediction        samples,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC) array        predSamples_(Cb) of chroma prediction samples for the component        Cb,    -   an (cbWidth/SubWidthC)×(cbHeight/SubHeightC) array        predSamples_(Cr) of chroma prediction samples for the component        Cr.        Let predSamplesLA_(L), and predSamplesLB_(L) be        (cbWidth)×(cbHeight) arrays of predicted luma sample values and,        predSamplesLA_(Cb), predSamplesLB_(Cb), predSamplesLA_(Cr) and        predSamplesLB_(Cr) be (cbWidth/SubWidthC)×(cbHeight/SubHeightC)        arrays of predicted chroma sample values.        The predSamples_(L), predSamples_(Cb) and predSamples_(Cr) are        derived by the following ordered steps:    -   1. For N being each of A and B, the following applies:        -   The reference picture consisting of an ordered            two-dimensional array refPicLN_(L) of luma samples and two            ordered two-dimensional arrays refPicLN_(Cb) and            refPicLN_(Cr) of chroma samples is derived by invoking the            process specified in clause 8.5.6.2 with X set equal to            predListFlagN and refIdxX set equal to refIdxN as input.        -   The array predSamplesLN_(L) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the luma coding            block width sbWidth set equal to cbWidth, the luma coding            block height sbHeight set equal to cbHeight, the motion            vector offset mvOffset set equal to (0, 0), the motion            vector mvLX set equal to mvN and the reference array            refPicLX_(L) set equal to refPicLN_(L), the variable            bdofFlag set equal to FALSE, the variable cIdx is set equal            to 0, and RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cb) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cb) set equal to refPicLN_(Cb), the variable            bdofFlagset equal to FALSE, the variable cIdx is set equal            to 1, and RefPicScale[predListFlagN][refIdxN] as inputs.        -   The array predSamplesLN_(Cr) is derived by invoking the            fractional sample interpolation process specified in clause            8.5.6.3 with the luma location (xCb, yCb), the coding block            width sbWidth set equal to cbWidth/SubWidthC, the coding            block height sbHeight set equal to cbHeight/SubHeightC, the            motion vector offset mvOffset set equal to (0, 0), the            motion vector mvLX set equal to mvCN, and the reference            array refPicLX_(Cr) set equal to refPicLN_(Cr), the variable            bdofFlag set equal to FALSE, the variable cIdx is set equal            to 2, and RefPicScale[predListFlagN][refIdxN] as inputs.    -   2. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to Table 36, with the        value of merge_geo_partition_idx[xCb][yCb], and the variable        isNarrowBlk set equal to cbHeight>cbWidth as inputs.    -   3. The value of merge_geo_parition_idx′[xCb][yCb] are set        according to the value of merge_geo_parition_idx[xCb][yCb] and        the coding block width cbWidth and the coding block height        cbHeight, as specified in Table xx.    -   4. The partition angle and distance of merge geo mode variable        angleIdx and distanceIdx are set according to the value of        merge_geo_partition_idx′[xCb][yCb] as specified in Table 36    -   5. The prediction samples inside the current luma co ding block,        predSamples_(L)[x_(L)][y_(L)] with x_(L)=0 . . . cbWidth−1 and        y_(L)=0 . . . cbHeight−1, are derived by invoking the weighted        sample prediction process for geo merge mode specified in clause        8.5.7.2 with the coding block widthnCbW set equal to cbWidth,        the coding block heightnCbH set equal to cbHeight, the sample        arrays predSamplesLA_(L) and predSamplesLB_(L), and the        variables angleIdx and distanceIdx, and cIdx equal to 0 as        inputs.    -   6. The prediction samples inside the current chroma component Cb        coding block, predSamples_(Cb)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cb) and predSamplesLB_(Cb), and the variables        angleIdx and distanceIdx, and cIdx equal to 1 as inputs.    -   7. The prediction samples inside the current chroma component Cr        coding block, predSamples_(Cr)[x_(C)][y_(C)] with x_(C)=0 . . .        cbWidth/SubWidthC−1 and y_(C)=0 . . . cbHeight/SubHeightC−1, are        derived by invoking the weighted sample prediction process for        geo merge mode specified in clause 8.5.7.2 with the coding block        width nCbW set equal to cbWidth/SubWidthC, the coding block        height nCbH set equal to cbHeight/SubHeightC, the sample arrays        predSamplesLA_(Cr) and predSamplesLB_(Cr), and the variables        angleIdx and distanceIdx, and cIdx equal to 2 as inputs.    -   8. The motion vector storing process for merge geo mode        specified in clause 8.5.7.3 is invoked with the luma coding        block location (xCb, yCb), the luma coding block width cbWidth,        the luma coding block height cbHeight, the partition direction        angleIdx and distanceIdx, the luma motion vectors mvA and mvB,        the reference indices refIdxA and refIdxB, and the prediction        list flags predListFlagA and predListFlagB as inputs.

FIG. 9G shows an example of this Table xx—Mapping table of thegeo_partition_idx′ values based on the geo_partition_idx value.

FIG. 9H shows Table 36—Specification of the angleIdx and distanceIdxvalues based on the merge_geo_partition_idx value.

High-Level Syntax Regarding Definitions of Intra Slices/Pictures

-   -   21. Instead of defining the intra (I) slice (or picture) as a        slice that is decoded using intra prediction only, it is        proposed to define the intra slice as a slice (or picture) that        is decoded without using inter prediction.        -   a. Alternatively, it is proposed to define the intra slice            as a slice that is decoded without referring to any pictures            rather than the picture containing the slice.        -   b. Alternatively, it is proposed to define the intra slice            as a slice that is decoded using intra prediction or intra            block copy (IBC) prediction or palette prediction mode.    -   22. It is proposed to define the intra picture as a picture that        is decoded without using inter prediction.        -   c. Alternatively, it is proposed to define the picture slice            as a picture that is decoded without referring to any            pictures rather than the picture containing the slice.        -   d. Alternatively, it is proposed to define the intra picture            as a picture that is decoded using intra prediction or intra            block copy (IBC) prediction or palette prediction mode.

Regarding Signaled Range of Subpicture Numbers

-   -   23. A conformance bitstream shall satisfy that when subpicture        is present, the number of subpictures shall be no smaller than        2.        -   a. Alternatively, furthermore, the signaled            sps_num_subpics_minus1 shall be in the range of 1 to N            (e.g., N=254).        -   b. Alternatively, furthermore, the signaled            sps_num_subpics_minus1 is replaced by            sps_num_subpics_minus2, wherein sps_num_subpics_minus2 plus            2 specifies the number of subpictures.            -   i. Alternatively, furthermore, the value of                sps_num_subpics_minus2 shall be in the range of 0 to                (N−1) (e.g., N=254).    -   24. A syntax element (e.g., whether to signal the syntax        element, or the semantics of the syntax elopement) which is        dependent on the subpicture present flag (e.g.,        subpics_present_flag) is replaced by checking whether        sps_num_subpics_minus1 is equal to 0.

FIG. 3 is a block diagram of a video processing apparatus 300. Theapparatus 300 may be used to implement one or more of the methodsdescribed herein. The apparatus 300 may be embodied in a smartphone,tablet, computer, Internet of Things (IoT) receiver, and so on. Theapparatus 300 may include one or more processors 302, one or morememories 304 and video processing hardware 306. The processor(s) 302 maybe configured to implement one or more methods described in the presentdocument. The memory (memories) 304 may be used for storing data andcode used for implementing the methods and techniques described herein.The video processing hardware 306 may be used to implement, in hardwarecircuitry, some techniques described in the present document. In someembodiments, the hardware 306 may be at least partly internal to theprocessor 302, e.g., a graphics co-processor.

FIG. 6 is a block diagram that illustrates an example video codingsystem 100 that may utilize the techniques of this disclosure.

As shown in FIG. 6, video coding system 100 may include a source device110 and a destination device 120. Source device 110 generates encodedvideo data which may be referred to as a video encoding device.Destination device 120 may decode the encoded video data generated bysource device 110 which may be referred to as a video decoding device.

Source device 110 may include a video source 112, video encoder 114, andan input/output (I/O) interface 116.

Video source 112 may include a source such as a video capture device, aninterface to receive video data from a video content provider, and/or acomputer graphics system for generating video data, or a combination ofsuch sources. The video data may comprise one or more pictures. videoencoder 114 encodes the video data from video source 112 to generate abitstream. The bitstream may include a sequence of bits that form acoded representation of the video data. The bitstream may include codedpictures and associated data. A coded picture is a coded representationof a picture. The associated data may include sequence parameter sets,picture parameter sets, and other syntax structures. I/O interface 116may include a modulator/demodulator (modem) and/or a transmitter. Theencoded video data may be transmitted directly to destination device 120via I/O interface 116 through network 130 a. The encoded video data mayalso be stored onto a storage medium/server 130 b for access bydestination device 120.

Destination device 120 may include an I/O interface 126, a video decoder124, and a display device 122.

I/O interface 126 may include a receiver and/or a modem. I/O interface126 may acquire encoded video data from the source device 110 or thestorage medium/the server 130 b. Video decoder 124 may decode theencoded video data. Display device 122 may display the decoded videodata to a user. Display device 122 may be integrated with thedestination device 120, or may be external to destination device 120which be configured to interface with an external display device.

Video encoder 114 and video decoder 124 may operate according to a videocompression standard, such as the High Efficiency Video Coding (HEVC)standard presently, VVM standard and other current and/or furtherstandard.

FIG. 7 is a block diagram illustrating an example of video encoder 200,which may be video encoder 112 in the system 100 illustrated in FIG. 6.

The video encoder 200 may be configured to perform any or all of thetechniques of this disclosure. In the example of FIG. 7, the videoencoder 200 includes a plurality of functional components. Thetechniques described in this disclosure may be shared among the variouscomponents of the video encoder 200. In some examples, a processor maybe configured to perform any or all of the techniques described in thisdisclosure.

The functional components of the video encoder 200 may include apartition unit 201, a predication unit 202 which may include a modeselect unit 203, a motion estimation unit 204, a motion compensationunit 205 and an intra prediction unit 206, a residual generation unit207, a transform unit 208, a quantization unit 209, an inversequantization unit 210, an inverse transform unit 211, a reconstructionunit 212, a buffer 213, and an entropy encoding unit 214.

In other examples, the video encoder 200 may include more, fewer, ordifferent functional components. In an example, the predication unit mayinclude an intra block copy (IBC) unit. The IBC unit may performpredication in an IBC mode in which at least one reference picture is apicture where the current video block is located.

Furthermore, some components, such as motion estimation unit 204 andmotion compensation unit 205 may be highly integrated, but arerepresented in the example of FIG. 7 separately for purposes ofexplanation.

partition unit 201 may partite a current picture into one or more videoblocks. The video encoder 200 and the video decoder 300 may supportvarious video block sizes.

Mode select unit 203 may select one of the coding modes, intra or inter,e.g., based on error results, and provides the resulting intra- orinter-coded block to a residual generation unit 206 to generate residualblock data and to a reconstruction unit 211 to reconstruct the encodedblock for use as a reference picture. In some example, Mode select unit203 may select a combination of intra and inter predication (CIIP) modein which the predication is based on a inter predication signal and aintra predication signal. Mode select unit 203 may also select aresolution fora motion vector (e.g., a sub-pixel or integer pixelprecision) for the block in the case of inter-predication.

To perform inter prediction on a current video block, motion estimationunit 204 may generate motion information for the current video block bycomparing one or more reference frames from buffer 213 to the currentvideo block. Motion compensation unit 205 may determine a predictedvideo block for the current video block based on the motion informationand decoded samples of pictures, from buffer 213 other than the pictureassociated with the current video block (e.g., reference pictures).

Motion estimation unit 204 and motion compensation unit 205 may performdifferent operations for a current video block, for example, dependingon whether the current video block is in an I slice, a P slice, or a Bslice.

In some examples, motion estimation unit 204 may perform uni-directionalprediction for the current video block, and motion estimation unit 204may search reference pictures of list 0 or list 1 for a reference videoblock for the current video block. Motion estimation unit 204 may thengenerate a reference index that indicates the reference picture in list0 or list 1 that contains the reference video block and a motion vectorthat indicates a spatial displacement between the current video blockand the reference video block. Motion estimation unit 204 may output thereference index, a prediction direction indicator, and the motion vectoras the motion information of the current video block. Motioncompensation unit 205 may generate the predicted video block of thecurrent block based on the reference video block indicated by the motioninformation of the current video block.

In other examples, motion estimation unit 204 may perform bi-directionalprediction for the current video block, motion estimation unit 204 maysearch the reference pictures in list 0 for a reference video block forthe current video block and may also search the reference pictures inlist 1 for another reference video block for the current video block.Motion estimation unit 204 may then generate reference indexes thatindicate the reference pictures in list 0 and list 1 containing thereference video blocks and motion vectors that indicate spatialdisplacements between the reference video blocks and the current videoblock. Motion estimation unit 204 may output the reference indexes andthe motion vectors of the current video block as the motion informationof the current video block. Motion compensation unit 205 may generatethe predicted video block of the current video block based on thereference video blocks indicated by the motion information of thecurrent video block.

In some examples, motion estimation unit 204 does not output a full setof motion information for the current video for example to entropyencoding unit 214. Rather, motion estimation unit 204 may signal themotion information of the current video block with reference to themotion information of another video block. For example, motionestimation unit 204 may determine that the motion information of thecurrent video block is sufficiently similar to the motion information ofa neighboring video block.

In one example, motion estimation unit 204 may indicate, in a syntaxstructure associated with the current video block, a value thatindicates to the video decoder 300 that the current video block has thesame motion information as the another video block.

In another example, motion estimation unit 204 may identify, in a syntaxstructure associated with the current video block, another video blockand a motion vector difference (MVD). The motion vector differenceindicates a difference between the motion vector of the current videoblock and the motion vector of the indicated video block. The videodecoder 300 may use the motion vector of the indicated video block andthe motion vector difference to determine the motion vector of thecurrent video block.

As discussed above, video encoder 200 may predictively signal the motionvector. Two examples of predictive signaling techniques that may beimplemented by video encoder 200 include advanced motion vectorpredication (AMVP) and merge mode signaling.

Intra prediction unit 206 may perform intra prediction on the currentvideo block. When intra prediction unit 206 performs intra prediction onthe current video block, intra prediction unit 206 may generateprediction data for the current video block based on decoded samples ofother video blocks in the same picture. The prediction data for thecurrent video block may include a predicted video block and varioussyntax elements.

Residual generation unit 207 may generate residual data for the currentvideo block by subtracting (e.g., indicated by the minus sign) thepredicted video block(s) of the current video block from the currentvideo block. The residual data of the current video block may includeresidual video blocks that correspond to different sample components ofthe samples in the current video block.

In other examples, there may be no residual data for the current videoblock for the current video block, for example in a skip mode, andresidual generation unit 207 may not perform the subtracting operation.

Transform processing unit 208 may generate one or more transformcoefficient video blocks for the current video block by applying one ormore transforms to a residual video block associated with the currentvideo block.

After transform processing unit 208 generates a transform coefficientvideo block associated with the current video block, quantization unit209 may quantize a transform coefficient video block associated with thecurrent video block based on a quantization parameter (QP) valueassociated with the current video block.

Inverse quantization unit 210 and inverse transform unit 211 may applyinverse quantization and inverse transforms to the transform coefficientvideo block, respectively, to reconstruct a residual video block fromthe transform coefficient video block. Reconstruction unit 202 may addthe reconstructed residual video block to corresponding samples from oneor more predicted video blocks generated by the predication unit toproduce a reconstructed video block associated with the current blockfor storage in the buffer 213.

After reconstruction unit 212 reconstructs the video block, loopfiltering operation may be performed reduce video blocking artifacts inthe video block.

Entropy encoding unit 214 may receive data from other functionalcomponents of the video encoder 200. When entropy encoding unit 214receives the data, entropy encoding unit 214 may perform one or moreentropy encoding operations to generate entropy encoded data and outputa bitstream that includes the entropy encoded data.

FIG. 8 is a block diagram illustrating an example of video decoder 300which may be video decoder 114 in the system 100 illustrated in FIG. 6.The video decoder 300 may be configured to perform any or all of thetechniques of this disclosure. In the example of FIG. 8, the videodecoder 300 includes a plurality of functional components. Thetechniques described in this disclosure may be shared among the variouscomponents of the video decoder 300. In some examples, a processor maybe configured to perform any or all of the techniques described in thisdisclosure.

In the example of FIG. 8, video decoder 300 includes an entropy decodingunit 301, motion compensation unit 302, intra prediction unit 303,inverse transformation unit 304, inverse quantization unit 305, andreconstruction unit 306 and buffer 307. Video decoder 300 may, in someexamples, perform a decoding pass generally reciprocal to the encodingpass described with respect to video encoder 200 (FIG. 7).

Entropy decoding unit 301 may retrieve an encoded bitstream. The encodedbitstream may include entropy coded video data (e.g., encoded blocks ofvideo data). Entropy decoding unit 301 may decode the entropy codedvideo data, and from the entropy decoded video data, motion compensationunit 302 may determine motion information including motion vectors,motion vector precision, reference picture list indexes, and othermotion information. Motion compensation unit 302 may, for example,determine such information by performing the AMVP and merge mode.

Motion compensation unit 302 may use motion vectors and/or MVDs receivedin the bitstream to identify a prediction video block in referencepicture in buffer 307.

Motion compensation unit 302 produces motion compensated blocks,possibly performing interpolation based on interpolation filters.Identifiers for interpolation filters to be used for motion estimationwith sub-pixel precision may be included in the syntax elements.

Motion compensation unit 302 may use interpolation filters as used byvideo encoder 20 during encoding of the video block to calculateinterpolated values for sub-integer pixels of a reference block. Motioncompensation unit 72 may determine the interpolation filters used byvideo encoder 20 according to received syntax information and use theinterpolation filters to produce predictive blocks.

Motion compensation unit 302 may uses some of the syntax information todetermine sizes of blocks used to encode frame(s) and/or slice(s) of theencoded video sequence, partition information that describes how eachmacroblock of a picture of the encoded video sequence is partitioned,modes indicating how each partition is encoded, one or more referenceframes (and reference frame lists) for each inter-encoded block, andother information to decode the encoded video sequence.

Intra prediction unit 303 may use intra prediction modes for examplereceived in the bitstream to form a prediction block from spatiallyadjacent blocks. Inverse quantization unit 303 inverse quantizes, i.e.,de-quantizes, the quantized video block coefficients provided in thebitstream and decoded by entropy decoding unit 301. Inverse transformunit 303 applies an inverse transform.

reconstruction unit 306 may sum the residual blocks with thecorresponding prediction blocks generated by motion compensation unit202 or intra-prediction unit 303 to form decoded blocks. If desired, adeblocking filter may also be applied to filter the decoded blocks inorder to remove blockiness artifacts. The decoded video blocks are thenstored in buffer 307, which provides reference blocks for subsequentmotion compensation and also produces decoded video for presentation ona display device and also produces decoded video for presentation on adisplay device.

The following solutions may be implemented as preferred solutions insome embodiments.

The following solutions may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item1).

1. A method of video processing (e.g., method 400 depicted in FIG. 4),comprising determining (402), for a conversion between a current blockof a video and a coded representation of the video, that a resolution ofa current picture containing the current block and a reference pictureused for the conversion are different, and performing (404) theconversion based on the determining such that predicted values of agroup of samples of the current block are generated using a horizontalor a vertical interpolation filter.

2. The method of solution 1, wherein the group of samples corresponds toall samples of the current block.

3. The method of solution 1, wherein the group of samples corresponds tosome samples of the current block.

4 The method of solution 3, wherein the group of samples corresponds toall samples of a region in the current block.

5. The method of any of solutions 1-4, wherein the group of samples isselected to have a same motion vector (MV) used during the conversion.

6. The method of any of solutions 1-4, wherein the group of samples havea same horizontal motion vector component.

7. The method of any of solutions 1-4, wherein the group of samples havea same vertical motion vector component.

8. The method of any of solutions 1-4, wherein the group of samples havea same fractional horizontal motion vector component part

9. The method of any of solutions 1-4, wherein the group of samples havea same fractional vertical motion vector component part.

10. The method of any of solutions 1-9, wherein, during the conversion,a motion vector for a specific sample is derived by modifying a value ofmotion vector derived based on the resolution of the current picture andthe resolution of the reference picture by a modification step includingtruncating, clipping or rounding.

11. The method of any of solutions 1-7, wherein, during the conversion,a motion vector for a specific sample is set to a value of a sharedmotion vector that is shared by all samples in the group of samples.

12. The method of any of solutions 1-9, wherein the group of samplesshare a shared motion vector during the conversion, and wherein theshared motion vector is derived from motion vectors of one or moresamples in the group of samples.

13. The method of solution 11, wherein the shared motion vector isfurther derived from a virtual sample.

The following solutions may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item5).

14. A method of video processing, comprising: determining, for aconversion between a current block of a video and a coded representationof the video, that a resolution of a current picture containing thecurrent block and a reference picture used for the conversion aredifferent, and performing the conversion based on the determining suchthat predicted values of a group of samples of the current block aregenerated as an interpolated version of a virtual reference block thatis generated by sample rate changing a region in the reference picture,wherein the sample rate changing depends on a height or a width of thecurrent picture or the reference picture.

15. The method of solution 14, wherein the interpolated version isgenerated using an interpolation filter whose coefficients do not dependon the height or the width of the current picture or the referencepicture.

The following solutions may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item6).

16. A method of video processing, comprising: determining, for aconversion between a current block of a video and a coded representationof the video, that a resolution of a current picture containing thecurrent block and a reference picture used for the conversion aredifferent, and based on the determining, deriving a top-left coordinateof a bounding block for reference sample padding based on a scheme thatis dependent on a height or a width of the current picture or thereference picture, and performing the conversion using the derivedtop-left coordinate of the bounding box.

17. The method of solution 16, the scheme comprises calculating lumasamples located at integer sample locations as:

xInt_(i)=Clip3(xSbInt_(L) −Dx,xSbInt_(L)+sbWidth+Ux,xInt),

yInt_(i)=Clip3(ySbInt_(L) −Dy,ySbInt_(L)+sbHeight+Uy,yInt_(i)),

where Dx and/or Dy and/or Ux and/or Uy depend on the width and/or theheight of the current picture or the reference picture, and wherein(xSbInt_(L), ySbInt_(L)) is the top left coordinate.

18. The method of solution 16, the scheme comprises calculating chromasamples located at integer sample locations as:

xInti=Clip3(xSbInt_(C) −Dx,xSbInt_(C)+sbWidth+Ux,xInti)

yInti=Clip3(ySbInt_(C) −Dy,ySbInt_(C)+sbHeight+Uy,yInti)

where Dx and/or Dy and/or Ux and/or Uy depend on the width and/or theheight of the current picture or the reference picture, and wherein(xSbInt_(L), ySbInt_(L)) is the top left coordinate.

The following solutions may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item7).

19. A method of video processing, comprising: determining, for aconversion between a current block in a current picture of a video and acoded representation of the video, a clipping operation applied tomotion vector calculation according to a bounding block for referencesample padding, based on use of a decoder side motion vector refinement(DMVR) during the conversion of the current block; and performing theconversion based on the clipping operation.

20. The method of solution 19, wherein the determining enables a legacyclipping operation due to the DMVR being used for the current block.

21. The method of any of solutions 19-20, wherein the current block is achroma block.

The following solutions may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item8).

22. A method of video processing, comprising: determining, for aconversion between a current block in a current picture of a video and acoded representation of the video, a clipping operation applied tomotion vector calculation according to a bounding block for referencesample padding, based on use of picture wrapping in the conversion; andperforming the conversion based on the clipping operation.

23. The method of solution 22, wherein the determining enables a legacyclipping operation only if the picture wrapping is disabled for thecurrent block.

24. The method of any of solutions 22-23, wherein the current block is achroma block.

25. The method of any of solutions 22-23, wherein the clipping operationis used to calculate luma samples as:

xInt_(i)=Clip3(xSbInt_(L) −Dx,xSbInt_(L)+sbWidth+Ux,xInt_(i)),

yInt_(i)=Clip3(ySbInt_(L) −Dy,ySbInt_(L)+sbHeight+Uy,yInt_(i)),

where Dx and/or Dy and/or Ux and/or Uy depend on the use of picturewrapping, and wherein (xSbInt_(L), ySbInt_(L)) represents the boundingblock.

26. The method of any of solutions 1 to 25, wherein the conversioncomprises encoding the video into the coded representation.

27. The method of any of solutions 1 to 25, wherein the conversioncomprises decoding the coded representation to generate pixel values ofthe video.

28. A video decoding apparatus comprising a processor configured toimplement a method recited in one or more of solutions 1 to 27.

29. A video encoding apparatus comprising a processor configured toimplement a method recited in one or more of solutions 1 to 27.

30. A computer program product having computer code stored thereon, thecode, when executed by a processor, causes the processor to implement amethod recited in any of solutions 1 to 27.

31. A method, apparatus or system described in the present document.

Various examples of preferred embodiments according to the disclosedtechnology are described below. In these examples, video encoding ordecoding based on various rules is described. These rules, for example,relate to conditions under which (and only under which) clippingoperations may be used for ensuring that a motion vector points toactual samples in a reference frame, instead of pointing outside areference frame.

The following examples may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item7).

1. A method of video processing (e.g., method 1000 shown in FIG. 10A),comprising: making a first determination (1002) about whether adecoder-side motion vector refinement (DMVR) tool is enabled for aconversion between a current block of a current picture of a video and acoded representation of the video; making a second determination (1004),based on the first determination, about whether or how to clip a motionvector according to a bounding block for reference sample padding in areference picture used for determining a prediction block for thecurrent block according to a rule, and performing (1006) the conversionbased on the first determination and the second determination; wherein,using the DMVR tool, an encoded motion vector from the codedrepresentation is refined prior to using for determining the predictionblock.

2. The method of example 1 wherein the rule specifies that the motionvector is clipped according to the bounding block in case that the DMVRtool is enabled for the current block and otherwise not clippedaccording to the bounding block in case that the DMVR tool is disabledfor the current block.

3. The method of examples 1-2, wherein, using clipping, in case that theDMVR tool is enabled for the current block, the luma samples at integersample locations, denoted as (xInt_(i), yInt_(i)) are clipped asfollows:

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))

yInt_(i)=Clip3(ySbInt_(L)−3,ySbInt_(L)+sbHeight+4,yInt_(i))

where (xSbInt_(L), ySbInt_(L)) is the top-left coordinate, sbWidth andsbHeight represent a width and a height of the current block andfunction Clip3( ) is defines as:

${Clip3( {x,y,z} )} = \{ {\begin{matrix}{x;} & {z < x} \\{y;} & {z > y} \\{z;} & {otherwise}\end{matrix}.} $

4. The method of examples 1-2, wherein, using clipping, in case that theDMVR tool is enabled for the current block, the chroma samples atinteger sample locations, denoted as (xInt_(i), yInt_(i)) are clipped asfollows:

xInt_(i)=Clip3(xSbInt_(C)−3,xSbInt_(L)+sbWidth+4,xInt_(i))

yInt_(i)=Clip3(ySbInt_(C)−3,ySbInt_(L)+sbHeight+4,yInt_(i))

where (xSbInt_(C), ySbInt_(C)) is the top-left coordinate, sbWidth andsbHeight represent a width and a height of the current block andfunction Clip3( ) is defines as:

${Clip3( {x,y,z} )} = \{ {\begin{matrix}{x;} & {z < x} \\{y;} & {z > y} \\{z;} & {otherwise}\end{matrix}.} $

5. The method of any of examples 1-4, wherein a syntax element isincluded in the coded representation indicative of whether the DMVR isenabled.

The following examples may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item8).

6. A method of video processing (e.g., method 1010 shown in FIG. 10B),comprising: making a first determination (1012) about whether referencepicture wrapping is enabled for a conversion between a current block ofa current picture of a video and a coded representation of the video;making a second determination (1014), based on the first determination,about whether or how to clip a motion vector according to a boundingblock for reference sample padding in a reference picture used fordetermining a prediction block for the current block according to arule, and performing (1016) the conversion based on the firstdetermination and the second determination.

7. The method of example 6 wherein the rule specifies that the motionvector is clipped according to the bounding block in case that referencepicture wrapping is enabled for the current block and otherwise notclipped according to the bounding block in case that reference picturewrapping is unavailable for the current block.

8. The method of examples 6-7, wherein, using clipping, the luma samplesat integer sample locations, denoted as (xInt_(i), yInt_(i)) are clippedas follows:

xInt_(i)=Clip3(xSbInt_(L)−3,xSbInt_(L)+sbWidth+4,xInt_(i))

yInt_(i)=Clip3(ySbInt_(L)−3,yShInt_(L)+sbHeight+4,yInt_(i))

where (xSbInt_(L), ySbInt_(L)) is the top-left coordinate, sbWidth andsbHeight represent a width and a height of the current block andfunction Clip3( ) is defines as:

${Clip3( {x,y,z} )} = \{ {\begin{matrix}{x;} & {z < x} \\{y;} & {z > y} \\{z;} & {otherwise}\end{matrix}.} $

9. The method of examples 6-7, wherein, using clipping, the chromasamples at integer sample locations, denoted as (xInt_(i), yInt_(i)) areclipped as follows:

xInt_(i)=Clip3(xSbInt_(C)−3,xSbInt_(L)+sbWidth+4,xInt_(i))

yInt_(i)=Clip3(ySbInt_(C)−3,ySbInt_(L)+sbHeight+4,yInt_(i))

where (xSbInt_(C), ySbInt_(C)) is the top-left coordinate, sbWidth andsbHeight represent a width and a height of the current block andfunction Clip3( ) is defines as:

${Clip3( {x,y,z} )} = \{ {\begin{matrix}{x;} & {z < x} \\{y;} & {z > y} \\{z;} & {otherwise}\end{matrix}.} $

10. The method of any of examples 6-9, wherein a syntax element isincluded in the coded representation indicative of whether the referencepicture wrapping is enabled for the current block.

11. The method of any of examples 6-10, wherein, using reference picturewrapping, a motion vector pointing to outside the bounding block iswrapped around to point to reference samples inside the bounding block.

The following examples may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item19).

12. A method of video processing (e.g., method 1020 shown in FIG. 10C),comprising: making a first determination (1022) about whether a codingtool is enabled for a conversion between a current block of a currentpicture of a video and a coded representation of the video; making asecond determination (1024), based on the first determination, aboutwhether or how to clip chroma or luma samples to integer positions in areference picture used for determining a prediction block for thecurrent block according to a rule, and performing (1026) the conversionbased on the first determination and the second determination.

13. The method of example 12, wherein the coding tool comprises adecoder side motion vector refinement tool in which a motion vectorcoded in the coded representation is refined prior to determining aprediction block for the current block.

14. The method of examples 12-13, wherein the rule specifies that theluma or chroma sample positions are clipped in case that the coding toolis enabled for the current block and otherwise not clipped in case thatthe coding tool is disabled for the current block.

15. The method of examples 12-13, wherein the rule specifies that theluma or chroma sample positions are clipped in case that the coding toolis disabled for the current block and otherwise not clipped in case thatthe coding tool is enabled for the current block.

The following examples may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item18(g)).

16. A method of video processing (e.g., method 1030 shown in FIG. 10D),comprising: determining (1032), for a conversion between a videocomprising a current picture comprising a current block and a codedrepresentation of the video, whether an integer sample clippingoperation is to be performed when generating a prediction block for thecurrent block from one or more reference pictures from two referencepicture lists, and performing (1034) the conversion based on thederiving, wherein the rule is based on a first size associated with thecurrent picture and/or a second size associated with the one or morereference pictures in the two reference picture lists or whether use ofdecoder-side motion vector refinement (DMVR) is enabled in which amotion vector coded in the coded representation is refined prior to thegenerating of the prediction block.

17. The method of example 16, wherein the first size corresponds to asize of the current picture or a size of a conformance window of thecurrent picture or a size of the scaling window of the current picture.

18. The method of any of examples 16-17, wherein the second sizecorresponds to a size of the one or more reference pictures in the tworeference picture lists or a size of a conformance window of the one ormore reference pictures in the two reference picture lists or a size ofthe scaling window of the one or more reference pictures in the tworeference picture lists.

19. The method of any of examples 16-18, wherein the rule specifiesthat, in case that the first size and the second size are equal, theinteger sample clipping operation is performed; and in case that thefirst size and the second size are unequal, the integer sample clippingoperation is disabled.

20. The method of any of examples 16-18, wherein the rule specifiesthat, in case that the first size and the second size are unequal, theinteger sample clipping operation is performed; and in case that thefirst size and the second size are equal, the integer sample clippingoperation is disabled.

21. The method of any of examples 16-18, wherein the first size and thesecond size are related by a scaling factor and wherein a syntax fieldis included in the coded representation indicative of the scalingfactor.

22. The method of example 16, wherein a syntax field is included in thecoded representation indicating that the DMVR is enabled.

23. The method of example 22, wherein the syntax field is a flag.

The following examples may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item6).

24. A method of video processing (e.g., method 1040 shown in FIG. 10E),comprising: deriving (1042), for a conversion between a video comprisinga current picture comprising a current block and a coded representationof the video, a top-left coordinate of a bounding box for referencesignal padding in a reference picture used for determining a predictionblock for the current block according to a rule, and performing (1044)the conversion based on the deriving, wherein the rule is based on adimension of the current picture or a dimension of the referencepicture.

25. The method of example 24, wherein the rule specifies values Dx, Dy,Ux or Uy that are used for determining luma samples at integer samplelocations, denoted as (xInt_(i), yInt_(i)) as follows:

xInt_(i)=Clip3(xSbInt_(L) −Dx,xSbInt_(L)+sbWidth+Ux,xInt_(i)),

yInt_(i)=Clip3(ySbInt_(L) −Dy,ySbInt_(L)+sbHeight+Uy,yInt_(i)),

where (xSbInt_(L), ySbInt_(L)) is the top-left coordinate, sbWidth andsbHeight represent a width and a height of the current block andfunction Clip3( ) is defines as:

${Clip3( {x,y,z} )} = \{ {\begin{matrix}{x;} & {z < x} \\{y;} & {z > y} \\{z;} & {otherwise}\end{matrix}.} $

26. The method of example 24, wherein the rule specifies values Dx, Dy,Ux or Uy that are used for determining chroma samples at integer samplelocations, denoted as (xInt_(i), yInt_(i)) as follows:

xInt_(i)=Clip3(xSbInt_(C) −Dx,xSbInt_(C)+sbWidth+Ux,xInt_(i))

yInt_(i)=Clip3(ySbInt_(C) −Dy,ySbInt_(C)+sbHeight+Uy,yInt_(i))

where (xSbInt_(C), ySbInt_(C)) is the top-left coordinate, sbWidth andsbHeight represent a width and a height of the current block andfunction Clip3( ) is defines as:

${Clip3( {x,y,z} )} = \{ {\begin{matrix}{x;} & {z < x} \\{y;} & {z > y} \\{z;} & {otherwise}\end{matrix}.} $

The following examples may be implemented together with additionaltechniques described in items listed in the previous section (e.g., item18).

27. A method of video processing (e.g., method 1050 shown in FIG. 10F),comprising: determining (1052), for a conversion between a videocomprising a current picture comprising a current block and a codedrepresentation of the video, whether an integer sample clippingoperation is to be performed when generating a prediction block for thecurrent block from a reference picture, and performing (1054) theconversion based on the deriving, wherein the rule is based on a firstsize associated with the current picture and/or a second size associatedwith the reference picture.

28. The method of example 27, wherein the first size associated with thecurrent picture corresponds to a size of the current picture or a sizeof a conformance window of the current picture or a size of the scalingwindow of the current picture.

29. The method of any of examples 27-28, wherein the second sizeassociated with the reference picture corresponds to a size of thereference picture or a size of a conformance window of the referencepicture or a size of the scaling window of the reference picture.

30. The method of any of examples 27-29, wherein the rule specifiesthat, in case that the first size and the second size are equal, theinteger sample clipping operation is performed; and in case that thefirst size and the second size are unequal, the integer sample clippingoperation is disabled.

31. The method of any of examples 27-29, wherein the rule specifiesthat, in case that the first size and the second size are unequal, theinteger sample clipping operation is performed; and in case that thefirst size and the second size are equal, the integer sample clippingoperation is disabled.

32. The method of any of examples 27-29, wherein the first size and thesecond size are related by a scaling factor between the current pictureand the reference picture.

33. The method of example 32, wherein the rule specifies to use theinteger sample clipping operation if and only if the scaling factor isequal to 1.

34. The method of example 32, wherein the rule specifies to use theinteger sample clipping operation if and only if the scaling factor isunequal to 1.

35. The method of any of examples 27-29, wherein the first sizeassociated with the current picture and the second size associated withthe reference picture are widths, and wherein the rule specifies to useinteger sample clipping operation in a horizontal direction.

36. The method of example 35, wherein the first size associated with thecurrent picture and the second size associated with the referencepicture are related by a horizontal scaling factor, and wherein the rulespecifies to use integer sample clipping operation in a horizontaldirection.

37. The method of any of examples 27-29, wherein the first sizeassociated with the current picture and the second size associated withthe reference picture are heights, and wherein the rule specifies to useinteger sample clipping operation in a vertical direction.

38. The method of example 37, wherein the first size associated with thecurrent picture and the second size associated with the referencepicture are related by a vertical scaling factor, and wherein the rulespecifies to use integer sample clipping operation in a verticaldirection.

39. The method of any of examples 35-38, wherein a syntax field includedin the coded representation is indicative of a floating pointrepresentation of the horizontal scaling factor and the vertical scalingfactor.

40. The method of example 39, wherein the horizontal scaling factor andthe vertical scaling factor are equal to (1<<14) where << is the leftbit shifting operation.

41. The method of any of examples 1 to 40, wherein the conversioncomprises encoding the video into the coded representation.

42. The method of any of examples 1 to 40, wherein the conversioncomprises decoding the coded representation to generate pixel values ofthe video.

43. A video decoding apparatus comprising a processor configured toimplement a method recited in one or more of examples 1 to 42.

44. A video encoding apparatus comprising a processor configured toimplement a method recited in one or more of examples 1 to 42.

45. A computer program product having computer code stored thereon, thecode, when executed by a processor, causes the processor to implement amethod recited in any of examples 1 to 42.

46. A non-transitory computer-readable storage medium storinginstructions that cause a processor to implement a method recited in anyof examples 1 to 42.

47. A non-transitory computer-readable recording medium storing abitstream corresponding to the coded representation that is generated bya method recited in any of examples 1 to 42.

48. A method, apparatus or system described in the present document.

In the above solutions, the performing the conversion includes using theresults of previous decision step during the encoding or decodingoperation to arrive at the conversion results.

In the present document, the term “video processing” may refer to videoencoding, video decoding, video compression or video decompression. Forexample, video compression algorithms may be applied during conversionfrom pixel representation of a video to a corresponding bitstreamrepresentation or vice versa. The bitstream representation, or codedrepresentation, of a current video block may, for example, correspond tobits that are either co-located or spread in different places within thebitstream, as is defined by the syntax. For example, a video block maybe encoded in terms of transformed and coded error residual values andalso using bits in headers and other fields in the bitstream.Furthermore, during conversion, a decoder may parse a bitstream with theknowledge that some fields may be present, or absent, based on thedetermination, as is described in the above solutions. Similarly, anencoder may determine that certain syntax fields are or are not to beincluded and generate the coded representation accordingly by includingor excluding the syntax fields from the coded representation.

Some embodiments of the disclosed technology, e.g., the above describedsolutions and examples, include making a decision or determination toenable a video processing tool or mode. In an example, when the videoprocessing tool or mode is enabled, the encoder will use or implementthe tool or mode in the processing of a block of video, but may notnecessarily modify the resulting bitstream based on the usage of thetool or mode. That is, a conversion from the block of video to thebitstream representation of the video will use the video processing toolor mode when it is enabled based on the decision or determination. Inanother example, when the video processing tool or mode is enabled, thedecoder will process the bitstream with the knowledge that the bitstreamhas been modified based on the video processing tool or mode. That is, aconversion from the bitstream representation of the video to the blockof video will be performed using the video processing tool or mode thatwas enabled based on the decision or determination.

Some embodiments of the disclosed technology include making a decisionor determination to disable a video processing tool or mode. In anexample, when the video processing tool or mode is disabled, the encoderwill not use the tool or mode in the conversion of the block of video tothe bitstream representation of the video. In another example, when thevideo processing tool or mode is disabled, the decoder will process thebitstream with the knowledge that the bitstream has not been modifiedusing the video processing tool or mode that was disabled based on thedecision or determination.

The disclosed and other solutions, examples, embodiments, modules andthe functional operations described in this document can be implementedin digital electronic circuitry, or in computer software, firmware, orhardware, including the structures disclosed in this document and theirstructural equivalents, or in combinations of one or more of them. Thedisclosed and other embodiments can be implemented as one or morecomputer program products, i.e., one or more modules of computer programinstructions encoded on a computer readable medium for execution by, orto control the operation of, data processing apparatus. The computerreadable medium can be a machine-readable storage device, amachine-readable storage substrate, a memory device, a composition ofmatter effecting a machine-readable propagated signal, or a combinationof one or more them. The term “data processing apparatus” encompassesall apparatus, devices, and machines for processing data, including byway of example a programmable processor, a computer, or multipleprocessors or computers. The apparatus can include, in addition tohardware, code that creates an execution environment for the computerprogram in question, e.g., code that constitutes processor firmware, aprotocol stack, a database management system, an operating system, or acombination of one or more of them. A propagated signal is anartificially generated signal, e.g., a machine-generated electrical,optical, or electromagnetic signal, that is generated to encodeinformation for transmission to suitable receiver apparatus.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand-alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this document can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read only memory ora random-access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto optical disks, or optical disks. However, a computerneed not have such devices. Computer readable media suitable for storingcomputer program instructions and data include all forms of non-volatilememory, media and memory devices, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks;magneto optical disks; and CD ROM and DVD-ROM disks. The processor andthe memory can be supplemented by, or incorporated in, special purposelogic circuitry.

While this patent document contains many specifics, these should not beconstrued as limitations on the scope of any subject matter or of whatmay be claimed, but rather as descriptions of features that may bespecific to particular embodiments of particular techniques. Certainfeatures that are described in this patent document in the context ofseparate embodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a sub combination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Moreover, the separation of various system components in theembodiments described in this patent document should not be understoodas requiring such separation in all embodiments.

Only a few implementations and examples are described and otherimplementations, enhancements and variations can be made based on whatis described and illustrated in this patent document.

1. A method of video processing, comprising: making a firstdetermination about whether a decoder-side motion vector refinement toolis enabled for a conversion between a current block of a current pictureof a video and a bitstream of the video; making a second determination,based on the first determination, about whether to clip samples atinteger sample locations according to a bounding block for referencesample padding in a reference picture used for determining a predictionblock for the current block, wherein the samples at the integer samplelocations are in the reference picture and are acquired according to afirst motion vector of the current block; and performing the conversionbased on the second determination.
 2. The method of claim 1 wherein thesamples at the integer sample locations are clipped according to thebounding block in case that the decoder-side motion vector refinementtool is enabled for the current block.
 3. The method of claim 1, whereinin case that the decoder-side motion vector refinement tool is enabledfor the current block, luma samples at the integer sample locations,denoted as (xInti, yInti) are clipped according to xSbIntL−3 andySbIntL−3; where (xSbIntL, ySbIntL) specifies a top-left sample of thebounding block relative to a top-left luma sample of the referencepicture.
 4. The method of claim 1, wherein in case that the decoder-sidemotion vector refinement tool is enabled for the current block, chromasamples at the integer sample locations, denoted as (xInti, yInti) areclipped xSbIntC−1 and ySbIntC−1; where (xSbIntC, ySbIntC) specifies atop-left sample of the bounding block relative to a top-left chromasample of the reference picture.
 5. The method of claim 2, wherein thefirst motion vector is refined by the decoder-side motion vectorrefinement tool.
 6. The method of claim 3, wherein (xSbIntL, ySbIntL) isdetermined based on a second motion vector which is not refined by thedecoder-side motion vector refinement tool.
 7. The method of claim 1,wherein the method further comprises: making a third determination aboutwhether reference picture wrapping is enabled for the conversion;performing the conversion based on the third determination; wherein howto clip the samples at the integer sample locations is based on whetherthe reference picture wrapping is enabled for the conversion.
 8. Themethod of claim 7, wherein a syntax element is included in the bitstreamindicative of whether the reference picture wrapping is enabled.
 9. Themethod of claim 7, wherein the second determination is used for a firstclip operation of the samples at integer sample locations and, whereinthe third determination is used fora second clip operation of thesamples at integer sample locations.
 10. The method of claim 1, whereinthe conversion comprises encoding the current block into the bitstream.11. The method of claim 1, wherein the conversion comprises decoding thecurrent block from the bitstream.
 12. An apparatus for processing videodata comprising a processor and a non-transitory memory withinstructions thereon, wherein the instructions upon execution by theprocessor, cause the processor to: make a first determination aboutwhether a decoder-side motion vector refinement tool is enabled for aconversion between a current block of a current picture of a video and abitstream of the video; make a second determination, based on the firstdetermination, about whether to clip samples at integer sample locationsaccording to a bounding block for reference sample padding in areference picture used for determining a prediction block for thecurrent block, wherein the samples at the integer sample locations arein the reference picture and are acquired according to a first motionvector of the current block; and perform the conversion based on thesecond determination.
 13. The apparatus of claim 12 wherein the samplesat the integer sample locations are clipped according to the boundingblock in case that the decoder-side motion vector refinement tool isenabled for the current block.
 14. The apparatus of claim 12, wherein incase that the decoder-side motion vector refinement tool is enabled forthe current block, luma samples at the integer sample locations, denotedas (xInti, yInti) are clipped according to xSbIntL−3 and ySbIntL−3;where (xSbIntL, ySbIntL) specifies a top-left sample of the boundingblock relative to a top-left luma sample of the reference picture. 15.The apparatus of claim 12, wherein in case that the decoder-side motionvector refinement tool is enabled for the current block, chroma samplesat the integer sample locations, denoted as (xInti, yInti) are clippedxSbIntC−1 and ySbIntC−1; where (xSbIntC, ySbIntC) specifies a top-leftsample of the bounding block relative to a top-left chroma sample of thereference picture.
 16. A non-transitory computer-readable storage mediumstoring instructions that cause a processor to: make a firstdetermination about whether a decoder-side motion vector refinement toolis enabled for a conversion between a current block of a current pictureof a video and a bitstream of the video; make a second determination,based on the first determination, about whether to clip samples atinteger sample locations according to a bounding block for referencesample padding in a reference picture used for determining a predictionblock for the current block, wherein the samples at the integer samplelocations are in the reference picture and are acquired according to afirst motion vector of the current block; and perform the conversionbased on the second determination.
 17. The medium of claim 16 whereinthe samples at the integer sample locations are clipped according to thebounding block in case that the decoder-side motion vector refinementtool is enabled for the current block.
 18. The medium of claim 16,wherein in case that the decoder-side motion vector refinement tool isenabled for the current block, luma samples at the integer samplelocations, denoted as (xInti, yInti) are clipped according to xSbIntL−3and ySbIntL−3; where (xSbIntL, ySbIntL) specifies a top-left sample ofthe bounding block relative to a top-left luma sample of the referencepicture.
 19. The medium of claim 16, wherein in case that thedecoder-side motion vector refinement tool is enabled for the currentblock, chroma samples at the integer sample locations, denoted as(xInti, yInti) are clipped xSbIntC−1 and ySbIntC−1; where (xSbIntC,ySbIntC) specifies a top-left sample of the bounding block relative to atop-left chroma sample of the reference picture.
 20. A non-transitorycomputer-readable recording medium storing a bitstream of a video whichis generated by a method performed by a video processing apparatus,wherein the method comprises: making a first determination about whethera decoder-side motion vector refinement tool is enabled for a conversionbetween a current block of a current picture of a video and a bitstreamof the video; making a second determination, based on the firstdetermination, about whether to clip samples at integer sample locationsaccording to a bounding block for reference sample padding in areference picture used for determining a prediction block for thecurrent block, wherein the samples at the integer sample locations arein the reference picture and are acquired according to a first motionvector of the current block, and generating the bitstream based on thesecond determination.